Blood Work
A test answers a particular question. Learn to identify that question, read the result and explain what the evidence leaves unresolved.
Start with the question, then read the result.
Start with the question a test can answer. A cell count, a chemical concentration, an antibody signal and a DNA pattern provide different kinds of evidence. This library connects the blood tests and related laboratory methods in PBS and Medical Interventions to that question. The PLTW section reflects the local course materials; the Other tests section adds common clinical examples. Use supplied fictional reports and teaching models here. Do not collect blood, prick a finger or enter anyone's health information.
- Top: plasma. Liquid portion of blood.
- Middle: white cells and platelets. A thin layer between plasma and red cells.
- Bottom: red cells. The packed red-cell layer.
Identify the report
Read the fictional case code, specimen, collection time and test name. A specimen is the material tested, such as whole blood, serum (the liquid left after blood clots) or a swab. Mark any missing field as not supplied.
Why this matters. The same method can test different materials. A result belongs to the labeled specimen and time, not to whichever case seems to fit.
Read all steps together
- Identify the report. Read the fictional case code, specimen, collection time and test name. A specimen is the material tested, such as whole blood, serum (the liquid left after blood clots) or a swab. Mark any missing field as not supplied. The same method can test different materials. A result belongs to the labeled specimen and time, not to whichever case seems to fit.
- Find the target. State what the test measures: cells, a chemical, an antigen, an antibody or genetic material. An antigen is a target recognized by an antibody; an antibody is an immune protein that binds a particular target. A result about one target does not answer every question about the patient or stain.
- Check the test's quality. For a classroom assay, inspect its supplied positive and negative controls before interpreting an unknown. An assay is a laboratory test. A control is a sample with an expected result. An unexpected control result can make the unknown result uninterpretable. Use the assay's own acceptance rules.
- Read the value and its key. Copy the value, units and the reference range or decision rule printed on that report. A reference range is the comparison interval for a particular test and population. For a pattern, use the supplied pattern key. A number without units or the right comparison rule cannot support a dependable interpretation. Children's and adults' ranges may differ.
- Explain within the evidence. Describe whether the supplied result is above, below or within its printed range, or what its pattern supports. Separate that observation from a possible explanation. Compare time points only when their methods and units are comparable. An out-of-range value is a reason to investigate. It does not, by itself, establish a diagnosis.
- Name the next question. State a missing fact, a test limitation or the further professional evaluation needed. Return to your assigned lesson for the actual product and submission directions. The strongest report makes its limits visible. These practice activities add no new submission and do not authorize laboratory work.
41 of 41 reference entries shown
Tests and methods in your courses
These entries connect to the local PBS or Medical Interventions course materials. Some are broader laboratory methods that can use blood, but also use other specimen types. Each card names that distinction and the course context.
Kastle-Meyer: presumptive blood screening PBS
PBS 1.1.4 Blood Evidence. Forensic screening asks whether a stain may contain blood; it is separate from a patient's clinical blood panel.
What it measures
A color reaction consistent with the activity of heme, the iron-containing part of hemoglobin. Presumptive means preliminary, requiring further evidence.
How to read the supplied evidence
- Read the supplied stain record and control results.
- Apply the stated color and timing rule only if those observations are supplied.
- Report a presumptive result and the need for appropriate follow-up.
What the result supports. A valid positive screen supports possible blood. Other materials can also react.
Where the claim stops. It does not prove human blood, identify a person or establish what happened. A negative screen is not proof that blood could never have been present. This page supplies no reagent or sampling procedure.
New Jersey State Police: Forensic Serology (source, opens in a new tab)
ABO blood typing PBS + MI
PBS 1.1.4 Blood Evidence and MI donor-compatibility work. ABO is a blood-group system with types A, B, AB and O.
What it measures
Whether red blood cells carry A and/or B antigens. Agglutination means visible clumping when the corresponding antibody reacts.
How to read the supplied evidence
- Use only the supplied teaching card or simulated blood.
- Read anti-A and anti-B reactions separately against their key.
- Call A, B, AB or O only when the pattern and quality checks support it.
What the result supports. With valid forward-typing results: anti-A clumping alone supports A; anti-B alone supports B; both support AB; neither supports O.
Where the claim stops. ABO is shared by many people, so the same type does not identify a person. Real clinical typing includes further checks. ABO alone does not establish Rh status or authorize a transfusion.
Forensic toxicology screening PBS
PBS 1.2.3 Forensic Toxicology. Toxicology studies substances and their harmful effects; the classroom task uses supplied records and concentration models.
What it measures
The presence or amount of selected drugs or other substances in a specified sample. Some tests use blood; others use urine or other materials.
How to read the supplied evidence
- Identify the named substance, specimen and method.
- Read the result and any concentration units or detection limit supplied.
- Separate a preliminary screen from a confirmed finding.
What the result supports. A supported result concerns the substances that this method actually tested for.
Where the claim stops. A screen does not test for every poison. Presence alone does not establish dose taken, impairment, timing or cause of death. Interpretations require method-specific confirmation and case context.
Forensic DNA profiling PBS
PBS 1.1.5 DNA Evidence and 1.1.6 DNA Analysis. A bloodstain can contain DNA-bearing cells, but DNA evidence can also come from other materials.
What it measures
Patterns at selected DNA markers, which are locations used to compare samples. This is different from ABO blood typing.
How to read the supplied evidence
- Read the sample labels, reference profiles and quality information.
- Compare every supplied marker using the stated rule.
- Record a supported exclusion or similarity and the limits of the comparison.
What the result supports. A complete, interpretable pattern may support further comparison. A classroom band match is a limited teaching observation.
Where the claim stops. A similar pattern does not establish when or how DNA arrived, who committed an act, or the source material by itself. Do not turn a classroom gel into a personal identification.
Complete blood count (CBC) PBS
PBS 2.1.4 Routine Testing: In the Lab. A panel is a group of related measurements reported together.
What it measures
Red blood cells, white blood cells and platelets, plus red-cell measurements such as hemoglobin and hematocrit. White cells help with immune defense; platelets help form clots.
How to read the supplied evidence
- Locate each named CBC row rather than treating CBC as one number.
- Keep counts, units and reference intervals together.
- Describe the pattern and what further information would be needed.
What the result supports. A CBC can reveal patterns that need evaluation, such as low red-cell measurements or changes in white-cell or platelet counts.
Where the claim stops. The same pattern can have different causes. A CBC alone does not identify a pathogen, prove cancer or measure blood glucose. A differential is an additional breakdown of white-cell types.
MedlinePlus: Complete blood count (source, opens in a new tab)
Hemoglobin (Hb or Hgb) PBS
A component of the CBC studied in PBS clinical bloodwork, not a separately verified PLTW activity.
What it measures
The concentration of hemoglobin, the protein in red blood cells that carries oxygen.
How to read the supplied evidence
- Find the Hb or Hgb row and its units.
- Compare it with that report's reference interval.
- Read it alongside other red-cell measurements and the fictional history.
What the result supports. A low result may support investigation for anemia, a reduced ability of blood to carry oxygen because of red-cell or hemoglobin problems.
Where the claim stops. The result does not establish the cause of anemia or measure the same thing as an oxygen-saturation sensor. Never use a class example to diagnose yourself or a classmate.
Hematocrit (Hct) PBS
A component of the CBC studied in PBS clinical bloodwork, not a separately verified PLTW activity.
What it measures
The proportion of whole blood volume occupied by red blood cells. It may be reported as a percentage or a fraction.
How to read the supplied evidence
- Read the Hct row and the way its units are written.
- Use the printed reference interval.
- Distinguish the red-cell volume fraction from a cell count or a hemoglobin concentration.
What the result supports. An unusual hematocrit can prompt investigation of red-cell status and hydration, the body's fluid balance.
Where the claim stops. It cannot name a single cause. A model tube illustrates the proportion; its appearance is not a real patient measurement.
Blood glucose PBS
PBS 2.1.4 Routine Testing: In the Lab and chronic-disease monitoring. Glucose is a sugar used by cells for energy.
What it measures
Glucose concentration at the time of testing. A laboratory plasma result and a home meter reading are not automatically interchangeable.
How to read the supplied evidence
- Check the stated sample, units, time and fasting status.
- Use the report's rule for that kind of glucose test.
- Compare comparable time points and describe the trend.
What the result supports. A result is a snapshot. A sequence of comparable readings can help a clinician assess a pattern.
Where the claim stops. A classroom value does not diagnose diabetes or distinguish type 1 from type 2. Diagnostic testing has specific criteria and often requires confirmation. Do not perform fingersticks for this page.
NIDDK: Diabetes tests and diagnosis (source, opens in a new tab)
Cholesterol and lipid panel PBS
PBS 2.1.4 Routine Testing: In the Lab. Lipids are fats and fat-like substances carried in blood.
What it measures
Total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol and triglycerides, a type of fat. The report should identify measured or calculated components.
How to read the supplied evidence
- Read each component separately with its units.
- Check the report's age-appropriate comparison rule and any preparation information.
- Describe the pattern without treating total cholesterol as the entire story.
What the result supports. Clinicians combine lipid results with other information when assessing cardiovascular risk.
Where the claim stops. A high result does not show that an artery is blocked. Adult thresholds do not automatically apply to children. Follow the ordering clinician's preparation instructions rather than assuming every test requires fasting.
MedlinePlus: Cholesterol levels (source, opens in a new tab)
ELISA: antigen or antibody testing MI
MI 1.1.5 ELISA. ELISA means enzyme-linked immunosorbent assay. Depending on its design, it can use serum, other samples or classroom substitutes; it is not blood-only.
What it measures
A particular antigen or antibody, using specific binding linked to a readable signal.
How to read the supplied evidence
- Identify the target and the assay format before reading color.
- Check supplied controls, then read unknowns against the stated cutoff or standard curve.
- Record the supported result and any failed quality check.
What the result supports. In the class's teaching ELISA, stronger signal can represent more target within the range covered by reliable standards.
Where the claim stops. Color alone does not identify an organism or amount. Signal rules depend on assay design, and food-dye models do not demonstrate actual antibody binding. A screening result may need further testing.
Serial dilution and standard curves MI
MI 1.1.4 Serial Dilutions and 1.1.5 ELISA. This is a supporting measurement method, not a separate clinical blood test.
What it measures
A known series of concentrations provides a comparison for an unknown signal. Dilution means reducing concentration by adding more solvent.
How to read the supplied evidence
- Read the supplied dilution factors and starting concentration.
- Track concentration at every step, including units.
- Use only the stated valid region of the standard curve to estimate an unknown.
What the result supports. A standard curve connects known concentrations to measured signals for a particular assay.
Where the claim stops. A darker food dye is a model signal, not proof of antigen. Do not extend a curve beyond its validated range or pretend a missing starting concentration is known.
FDA: Bioanalytical method validation guidance (source, opens in a new tab)
Polymerase chain reaction (PCR) MI
MI 2.1.2 Copying Our Genes. PCR is a laboratory technique that may be part of a test on blood, saliva, tissue or another suitable sample.
What it measures
PCR makes many copies of a selected DNA region. Primers are short DNA pieces that select the region to copy.
How to read the supplied evidence
- Identify the assay's target and the specimen in the supplied record.
- Check controls for target detection and contamination.
- Read the stated detection rule or downstream analysis.
What the result supports. The supported conclusion concerns the target covered by that assay and its validated detection rules.
Where the claim stops. PCR does not copy every gene or identify every disease. Copying DNA is not, by itself, a complete clinical interpretation. Do not infer a pathogen from an unvalidated classroom signal.
NHGRI: Polymerase chain reaction (source, opens in a new tab)
DNA gel electrophoresis PBS + MI
PBS DNA analysis and MI testing methods. Electrophoresis uses an electric field to separate molecules; a DNA gel is not automatically a blood test.
What it measures
A pattern of DNA fragments separated mainly by size in a standard agarose-gel model. A DNA ladder supplies fragments of known sizes for comparison.
How to read the supplied evidence
- Read lane labels, the ladder and quality information.
- Compare the entire supplied pattern using its interpretation key.
- State what the fragments support and what they do not reveal.
What the result supports. For comparable DNA fragments under the stated conditions, smaller fragments travel farther through the gel.
Where the claim stops. Equal apparent fragment size does not establish identical sequence or a disease-causing effect. A DNA gel and hemoglobin electrophoresis analyze different targets.
DNA and gene-expression microarrays MI
MI 3.1.4 DNA Microarray. This related genetic method can use material from many specimen types and is not a routine blood panel.
What it measures
Many selected genetic targets at once through binding to complementary probes. Expression arrays study RNA-derived signals about gene activity. RNA carries information copied from DNA. Other arrays study DNA variants, or sequence differences.
How to read the supplied evidence
- Determine whether the supplied array studies DNA variants or gene expression.
- Read the legend, reference sample and normalization information supplied.
- Compare signals only by that dataset's rules.
What the result supports. A difference in expression can support a statement about relative gene activity in the tested samples.
Where the claim stops. Expression is not the same as a DNA mutation. An association or heat-map pattern does not prove that a gene caused a disease, and an array does not test every possible variant.
NHGRI: DNA microarray technology (source, opens in a new tab)
Karyotyping: a chromosome picture PBS
PBS 2.2.4 Clues in the Chromosomes. Cells for a clinical karyotype may come from blood or another tissue.
What it measures
Chromosome number and large-scale structure. A chromosome is a packaged DNA molecule; a karyotype arranges chromosome images for inspection.
How to read the supplied evidence
- Read the specimen and image source.
- Use the supplied size, banding and centromere clues to organize the image.
- Report the chromosome observation supported by the picture.
What the result supports. A karyotype may reveal a difference in chromosome number or a large structural change.
Where the claim stops. It cannot find every DNA variant. A classroom image does not provide every clinical detail or establish a person's full health status.
Alberta Health Services: Karyotype testing (source, opens in a new tab)
Blood urea nitrogen (BUN) MI
MI kidney-function and dialysis work. Dialysis is a treatment that removes some wastes and extra fluid when the kidneys cannot do enough of that work.
What it measures
Urea nitrogen, a waste product from protein breakdown that the kidneys normally remove from blood.
How to read the supplied evidence
- Read the BUN value with its units and time.
- Compare the report's range and comparable readings across the supplied session.
- Describe the waste-removal pattern rather than inventing a treatment decision.
What the result supports. A change can provide evidence about waste levels during the modeled dialysis session.
Where the claim stops. BUN also depends on factors such as hydration and protein breakdown. One result does not establish kidney failure or prove that a person no longer needs treatment.
Creatinine and estimated GFR (eGFR) MI
MI kidney-function work. GFR means glomerular filtration rate, a measure of kidney filtration; eGFR is an estimate rather than a direct count of filtering units.
What it measures
Creatinine is a muscle-related waste product measured in blood. Its result helps calculate an estimate of kidney filtration.
How to read the supplied evidence
- Distinguish the creatinine row from the eGFR row.
- Keep each result with its own units and report-specific interpretation.
- Compare the supplied clinical context and trends.
What the result supports. The pair helps a clinician assess kidney filtration alongside other information.
Where the claim stops. Muscle mass, medicines and other factors can affect interpretation. An eGFR is calculated, not a separate substance in the blood, and one class result does not diagnose a condition.
HLA tissue typing MI
MI transplant matching. HLA means human leukocyte antigen, a group of cell markers involved in immune recognition.
What it measures
HLA types used to compare a donor and recipient. This comparison is distinct from ABO blood typing.
How to read the supplied evidence
- Read the supplied HLA key and donor/recipient records.
- Compare only the markers supplied.
- Keep the HLA comparison separate from the crossmatch result.
What the result supports. A closer HLA match can be one useful part of a transplant evaluation.
Where the claim stops. A matching count alone cannot approve a transplant. Blood type, antibodies, crossmatching and other clinical factors also matter.
Alberta Health Services: Kidney-donor blood tests (source, opens in a new tab)
Donor-recipient crossmatch MI
MI donor-compatibility work. A crossmatch asks whether recipient antibodies react to a particular donor, rather than simply counting HLA similarities.
What it measures
Evidence of an immune reaction relevant to that donor-recipient pair.
How to read the supplied evidence
- Read the supplied positive/negative key.
- Record each pair's crossmatch separately from its HLA match count.
- Explain how a concerning reaction affects that pair's evaluation.
What the result supports. A positive crossmatch can indicate antibodies that may attack donor cells and raise rejection risk.
Where the claim stops. Positive does not mean a good match. A negative result does not guarantee success. A transplant team makes the decision using the full evaluation.
NHS Blood and Transplant: Histocompatibility testing (source, opens in a new tab)
Restriction digestion and RFLP: the HaeIII connection MI
MI testing methods and the October 26 HaeIII prediction lesson. Restriction digestion means cutting DNA with a sequence-selective enzyme. This related genetic method is not blood-only; the class's tasting-gene work uses cheek-cell DNA.
What it measures
Differences in the lengths of DNA fragments after cutting. RFLP means restriction fragment length polymorphism: a sequence difference can add or remove a recognized cut site. HaeIII is one restriction enzyme.
How to read the supplied evidence
- Read the supplied enzyme's recognition rule and the fictional sequence.
- Mark the supported cut sites and predict fragments from that sequence.
- Compare the complete predicted and observed pattern using the supplied gel key and controls.
What the result supports. Different cutting patterns can provide evidence about a tested DNA marker. The enzyme cuts DNA; PCR copies DNA; a gel separates the resulting fragments.
Where the claim stops. A fragment pattern does not by itself prove a disease or a whole person's traits. An incomplete digest can mislead, and a faint fragment may not be visible. Use only supplied practice data; this page gives no reaction or sampling protocol.
NHGRI: Restriction fragment length polymorphism (source, opens in a new tab)
SNP genotyping and carrier-testing evidence MI
MI 2.1.3 Test Your Own Genes and the supplied genotype/pedigree work. The reference uses fictional records, not personal genetic testing. DNA can come from blood or other appropriate material; the tasting-gene classroom example uses cheek cells.
What it measures
A genotype at a tested DNA position. A single nucleotide polymorphism (SNP, pronounced snip) is a DNA-letter variant at one position. An allele is a version at a genetic location.
How to read the supplied evidence
- Read the assayed position and the meaning of each supplied allele.
- Keep a genotype observation separate from the trait prediction.
- Use the stated inheritance model and pedigree to evaluate a carrier claim.
What the result supports. A tested variant may help track a trait or inform a defined genetic-test question.
Where the claim stops. A marker associated with a trait is not automatically its cause. A tasting trait is not a disease-carrier result. One assayed position does not reveal every genetic variant or predict an entire person's health.
NHGRI: Single nucleotide polymorphisms (source, opens in a new tab)
DNA sequencing MI
MI 1.1.3 Using DNA to Identify Pathogens includes automated DNA sequencing before database comparison. Sequencing is a laboratory method, not a routine blood-panel row, and it is not restricted to blood samples.
What it measures
The order of the A, T, C and G chemical letters, or bases, in a selected DNA region.
How to read the supplied evidence
- Identify the supplied sequence and its specimen label.
- Read the provided base calls and any quality or unknown-call information.
- Keep sequence generation separate from a later BLAST comparison or clinical interpretation.
What the result supports. A usable sequence provides a DNA-letter record that can be compared with a reference or database.
Where the claim stops. Sequencing a region does not establish the entire genome, the original specimen type or a disease diagnosis. Poor-quality or missing base calls must remain uncertain rather than being filled in by guesswork.
NHGRI: DNA sequencing fact sheet (source, opens in a new tab)
Protein gel electrophoresis and SDS-PAGE MI
MI 4.1.3 Protein Purification and the December 4 DNA-gel/protein-gel comparison. This related method separates proteins from suitable samples, not only blood. A classroom bacterial protein extract is not a patient blood specimen.
What it measures
A pattern of separated proteins. In SDS-PAGE, sodium dodecyl sulfate helps make protein migration depend mainly on size as proteins move through a polyacrylamide gel.
How to read the supplied evidence
- Identify the protein lanes, marker ladder and staining information supplied.
- Compare an unknown band with the protein-size markers, using the stated rule.
- Describe visible bands and the limits of any purity claim.
What the result supports. A protein ladder helps estimate apparent protein size. Fewer visible bands may support a more limited mixture under the tested conditions.
Where the claim stops. A band does not identify a protein by itself. Different proteins can travel together, and small amounts may escape detection. One visible band is not proof of complete purity. This is different from a DNA gel.
Western blot: detecting a target protein MI
The MI December 7 lesson compares a protein stain with a Western blot. Western blotting can analyze proteins from blood or tissue and is not a blood-only test.
What it measures
Antibody-based detection of a particular protein after proteins have been separated and transferred to a membrane, a thin supporting sheet.
How to read the supplied evidence
- Identify the target protein, sample lanes and supplied controls.
- Read the antibody-detected band at the expected size using the provided interpretation rule.
- Distinguish the target-specific result from a general protein-staining image.
What the result supports. A supported band provides evidence about the target protein in the tested sample.
Where the claim stops. An antibody can bind unintended targets, and detection depends on test quality. A visible band is not a diagnosis by itself. A Western blot detects protein rather than reading DNA sequence.
Alternate light source: visual screening PBS
PBS evidence-intake reading. An alternate light source helps reveal material under selected lighting conditions. The supplied fluorescent model is a visual teaching comparison, not a blood-identification assay.
What it measures
A visible response under the stated light and filter conditions. Fluorescence means material absorbs light and emits light at another wavelength.
How to read the supplied evidence
- Read the reported light conditions and image reference.
- Describe only the visible response actually supplied.
- Keep a visual screening observation separate from chemical identification.
What the result supports. A response can help locate material that needs further examination.
Where the claim stops. Fluorescence does not identify a substance as blood, and missing image information is not a negative finding. Luminol's chemically generated light is a different mechanism. Do not inspect a UV source or improvise equipment use.
NIJ/FTCoE: Landscape study of alternate light sources (source, opens in a new tab)
Luminol: light from a chemical screen PBS
PBS evidence-intake reading explicitly distinguishes luminol from the fluorescent classroom model. Luminol is a forensic screening method, not clinical bloodwork or a classroom reagent instruction.
What it measures
A chemically generated glow that may indicate traces requiring further examination. Chemiluminescence means light produced by a chemical reaction.
How to read the supplied evidence
- Identify whether the supplied record actually names a luminol test.
- Read the reported reaction and quality information without inventing observations.
- Report the screening limit and need for an appropriate identification method.
What the result supports. A reaction may support further investigation of possible bloodstains.
Where the claim stops. Other materials can react. A glow does not confirm human blood, identify a person or show what happened. The fluorescent classroom model does not reproduce a luminol test.
New Jersey State Police: Forensic Serology (source, opens in a new tab)
DNA-sequence comparison with BLAST MI
MI 1.1.3 Using DNA to Identify Pathogens. This computer-analysis method uses a supplied sequence; it is not a blood test or proof that the original specimen was blood.
What it measures
Similarity between a supplied DNA sequence and sequences in a database. A sequence is the order of DNA's chemical letters.
How to read the supplied evidence
- Use only the fictional, teacher-supplied sequence.
- Compare its match coverage and significance using the lesson's key.
- State which database match the sequence supports and what clinical evidence is still missing.
What the result supports. A strong sequence match can help identify the organism represented by the supplied sequence.
Where the claim stops. A database match alone does not prove that an organism caused the patient's illness, establish the specimen source or exclude contamination. Do not upload a real person's genetic data.
NCBI: Basic Local Alignment Search Tool (source, opens in a new tab)
Other blood tests
These additional clinical tests extend the same reasoning. Their inclusion here does not mean they are a named PLTW activity or an assigned task. This is a selected reference, not an exhaustive medical test directory.
Prenatal cell-free DNA screening (NIPT) PBS + MI
Other tests: blood-based background for prenatal-testing discussions. A prenatal guide is named in the MI schedule, but this specific method was not established as a required PLTW task by the local records inspected.
What it measures
Patterns in cell-free DNA fragments in a pregnant person's blood. Some fragments come from the placenta, the organ supporting the pregnancy, and can inform screening for selected chromosome conditions.
How to read the supplied evidence
- Check which conditions the supplied screening report covers.
- Read its probability or risk statement and any quality limitations.
- Distinguish a screening result from a diagnostic test result.
What the result supports. The result can indicate increased or decreased chance of the conditions included in that screen.
Where the claim stops. It is not a diagnosis and does not screen for every genetic condition. Positive and negative results can be incorrect; professional counseling and appropriate diagnostic follow-up may be needed. Amniocentesis and chorionic-villus sampling use different specimens and are not blood tests.
MedlinePlus Genetics: Noninvasive prenatal testing (source, opens in a new tab)
Hemoglobin A1C (HbA1c) PBS + MI
Other tests: a clinical connection to the PBS glucose-monitoring story. No separate local PLTW A1C task was verified.
What it measures
The percentage of hemoglobin with glucose attached. It reflects average blood glucose over roughly the preceding three months.
How to read the supplied evidence
- Recognize that the result is a percentage, not a glucose concentration.
- Compare it with the report's decision rule.
- Distinguish its longer time window from a single glucose reading.
What the result supports. Clinicians use A1C in diabetes evaluation and monitoring when the test is appropriate.
Where the claim stops. It does not show a sudden glucose change. Some blood conditions and other factors can affect accuracy, so a clinician may choose another test.
NIDDK: The A1C test and diabetes (source, opens in a new tab)
Rh(D) typing PBS + MI
Other tests: a clinical extension of ABO typing. The local PBS serology record supplies anti-A and anti-B results, not an Rh result.
What it measures
Whether the D antigen, commonly called the Rh factor, is present on red blood cells.
How to read the supplied evidence
- Check whether an actual anti-D result and valid controls were supplied.
- Use that test's interpretation key.
- If Rh evidence is absent, report Rh status as not supplied.
What the result supports. A valid Rh(D) test can support the positive or negative part of an ABO/Rh blood type.
Where the claim stops. Do not infer Rh status from ABO reactions. Clinical testing resolves weak or unclear reactions and uses more information before transfusion decisions.
American Red Cross: Blood types (source, opens in a new tab)
Basic metabolic panel (BMP) PBS + MI
Other tests: a common clinical panel that brings several chemical measurements together.
What it measures
Glucose, calcium, sodium, potassium, chloride, carbon dioxide, BUN and creatinine. Electrolytes are substances that carry electrical charge in body fluids.
How to read the supplied evidence
- Read all supplied rows and their units.
- Group the results by the questions they inform, such as glucose, fluid balance or kidney function.
- Use the report's own ranges and clinical context.
What the result supports. The pattern can help a clinician investigate chemical balance and organ function.
Where the claim stops. A BMP is not a CBC and does not count blood cells. A high or low chemical result may have several causes.
MedlinePlus: Basic metabolic panel (source, opens in a new tab)
Comprehensive metabolic panel (CMP) PBS + MI
Other tests: a broader clinical chemistry panel related to the BMP.
What it measures
The BMP measurements plus albumin, total protein, bilirubin and selected enzymes associated with liver assessment. Enzymes are proteins that speed chemical reactions.
How to read the supplied evidence
- Read the panel's actual list rather than assuming all panels contain the same rows.
- Separate kidney-related, liver-related and other findings.
- Explain a pattern using the report's units and ranges.
What the result supports. A CMP gives several clues about body chemistry that a clinician considers together.
Where the claim stops. A panel cannot, by itself, identify every liver or kidney condition. An enzyme can have more than one tissue source.
MedlinePlus: Comprehensive metabolic panel (source, opens in a new tab)
Liver panel PBS + MI
Other tests: focused clinical testing related to liver health.
What it measures
A selected group of substances, such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST), two enzymes; albumin, a protein; and bilirubin, a waste from red-cell breakdown. The ordered panel determines the exact list.
How to read the supplied evidence
- Expand each abbreviation using the report key.
- Read the pattern across the named tests.
- State a liver-related question that the clinician would investigate.
What the result supports. Some results give clues about tissue injury; others provide information about liver-related functions.
Where the claim stops. An unusual value does not identify a specific disease. Results need history, medicines and sometimes further testing or imaging.
MedlinePlus: Liver function tests (source, opens in a new tab)
Thyroid-stimulating hormone (TSH) PBS + MI
Other tests: a hormone-feedback example. Hormones are chemical messengers carried through the body.
What it measures
TSH, a signal from the pituitary gland at the base of the brain that tells the thyroid to make thyroid hormones.
How to read the supplied evidence
- Identify TSH rather than confusing it with a thyroid hormone itself.
- Compare the report's range.
- Read any supplied thyroid-hormone tests alongside it.
What the result supports. The pattern helps a clinician assess thyroid regulation.
Where the claim stops. TSH alone does not show the cause of a thyroid problem. Medicines, pregnancy and other conditions can affect interpretation.
Clotting tests: PT/INR and aPTT PBS + MI
Other tests: laboratory assessment of parts of the clotting system. Coagulation means clot formation.
What it measures
How long a sample takes to clot under specified laboratory conditions. INR is an international normalized ratio derived from prothrombin time (PT). Activated partial thromboplastin time (aPTT) examines a different set of clotting factors.
How to read the supplied evidence
- Identify which clotting test was ordered.
- Distinguish seconds from an INR ratio.
- Read the result using the report's rule and any supplied treatment context.
What the result supports. The results can help investigate unusual bleeding or monitor certain medicines.
Where the claim stops. These tests are not platelet counts and do not test every cause of bleeding. Do not adjust anyone's medicines from classroom examples.
MedlinePlus: Prothrombin time and INR (source, opens in a new tab)
C-reactive protein (CRP) PBS + MI
Other tests: a marker related to inflammation, the body's protective response to injury or illness.
What it measures
A protein made by the liver that often increases during inflammation.
How to read the supplied evidence
- Check the test type, units and printed range.
- Compare any supplied time points.
- Separate evidence of inflammation from an explanation of its cause.
What the result supports. An increased result can support further investigation or monitoring of inflammation.
Where the claim stops. CRP does not identify where inflammation is happening or which organism or disease caused it.
Ferritin and iron studies PBS + MI
Other tests: follow-up examples for questions about iron stores and red-cell production.
What it measures
Ferritin, a protein that stores iron. A broader iron study includes other measurements selected by the clinician.
How to read the supplied evidence
- Distinguish ferritin from hemoglobin.
- Read the report's units and range.
- Consider the supplied CBC and clinical context.
What the result supports. Ferritin helps a clinician investigate iron storage.
Where the claim stops. Ferritin can rise with inflammation as well as increased iron stores. A result alone does not justify taking iron supplements.
MedlinePlus: Ferritin blood test (source, opens in a new tab)
Blood culture PBS + MI
Other tests: a bloodstream-infection application of the courses' microbiology ideas. It is not the same as the classroom environmental culture lab.
What it measures
Whether bacteria or fungi grow from a clinical blood specimen under the laboratory's conditions.
How to read the supplied evidence
- Read the specimen, timing and laboratory report.
- Check whether growth was identified and whether contamination was considered.
- Distinguish culture results from a cell count or an antibody test.
What the result supports. Growth can prompt identification and further professional evaluation for a bloodstream infection.
Where the claim stops. Contamination can produce misleading growth, and no growth does not exclude every infection. Do not collect or culture blood in this classroom activity.
MedlinePlus: Bacteria culture test (source, opens in a new tab)
Cardiac troponin PBS + MI
Other tests: a clinical example of a protein marker released with heart-muscle injury.
What it measures
Troponin I or T in blood, using a specific clinical assay.
How to read the supplied evidence
- Identify the assay, units and time after symptoms in the supplied record.
- Read any repeated values and the laboratory's decision rule.
- Keep the laboratory evidence separate from the final clinical diagnosis.
What the result supports. An increase can indicate heart-muscle injury and is considered alongside symptoms and heart tests.
Where the claim stops. Troponin can rise for reasons other than a heart attack. Classroom interpretation must not delay urgent professional help for actual symptoms.
Arterial blood gas (ABG) PBS + MI
Other tests: a clinical connection to breathing and oxygen transport. An artery and a vein can provide different kinds of blood-gas information.
What it measures
Oxygen, carbon dioxide and acid-base information in an arterial blood sample. pH describes acidity.
How to read the supplied evidence
- Identify the specimen as arterial before using its interpretation rules.
- Keep oxygen, carbon dioxide and pH values separate.
- Connect the supplied pattern to a question about breathing or chemical balance.
What the result supports. The pattern helps clinicians assess gas exchange and acid-base balance.
Where the claim stops. A fingertip pulse oximeter estimates oxygen saturation; it does not supply an ABG's carbon dioxide or pH results. This is a report-reading reference, not a blood-sampling procedure.
MedlinePlus: Arterial blood gas test (source, opens in a new tab)
Hemoglobin electrophoresis PBS + MI
Other tests: a clinical extension of the courses' separation-method and genetic-disease ideas. No separate local PLTW hemoglobin-electrophoresis task was verified.
What it measures
The types and relative amounts of hemoglobin proteins in blood, including variants such as hemoglobin S.
How to read the supplied evidence
- Check that the report analyzes hemoglobin proteins, not DNA fragments.
- Read the identified types and their proportions.
- Use the laboratory interpretation and supplied history.
What the result supports. The pattern can help investigate inherited hemoglobin disorders.
Where the claim stops. A protein pattern is not a DNA sequence. Age, transfusion history and other information can affect interpretation; do not diagnose a classmate from a model.
MedlinePlus: Hemoglobin electrophoresis (source, opens in a new tab)
Make an interpretation you can defend.
Read a simulated blood-typing card
Antibodies in a test reagent bind their matching red-cell antigens, markers on the cell surface. In this simplified model, visible clumping with anti-A, anti-B or anti-D indicates the corresponding antigen. Anti-D checks one Rh antigen. The control must stay free of clumps.
Original invented practice data. This model is not a real laboratory protocol or a transfusion-compatibility decision. It does not model weak variants, reverse typing or a clinical crossmatch.
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A cells react with anti-A; B cells react with anti-B; AB cells react with both; O cells react with neither. In this model, anti-D clumping is reported as Rh positive.
Background: American Red Cross: blood types. This practice supplies a simplified forward-typing rule, not a clinical typing protocol.
Keep the method beside the evidence.
PBS and Medical Interventions lab manualsChoose your course, locate the named activity, and follow the teacher's approved model procedure. A reference page does not authorize handling human blood.Pre-lab simulation catalogChoose your course and find blood evidence, blood tests, ELISA, DNA or kidney investigations. Rehearse the reasoning with supplied fictional evidence.How to understand a laboratory report (opens in a new tab)National Library of Medicine explanation of reference ranges, positive/negative results, false results and interpretation limits.Use simulated blood and supplied records in class. Blood draws, lancets, specimen handling and real clinical testing require trained personnel and approved procedures; they are outside this reference activity.
Can you trace every claim to a result?
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A positive result needs a precise meaning.
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