Interpret Toxicology Evidence
Compare toxicology results to cutoffs and controls before making an evidence claim.
- Use a reference chart: Indicators and microscope features must be compared to a known guide.
- Structure and function: Students connect visible features to what tissues or molecules do.
Prerequisites are inferred: pending teacher review.
Re-learn the skill with worked practice and clear examples.
Compare toxicology results to cutoffs and controls before making an evidence claim.
| Substance | Result | Reference limit |
|---|---|---|
| Drug A | 4 ng/mL | under 5 = negative |
| Drug B | 18 ng/mL | 10 or more = positive |
| Control | expected | valid run |
Use the toxicology table. Which substance is below its reference limit?
Reviewed| Substance | Result | Reference limit |
|---|---|---|
| Drug A | 4 ng/mL | under 5 = negative |
| Drug B | 18 ng/mL | 10 or more = positive |
| Control | expected | valid run |
- A.The control row
- B.Drug A
- C.Drug B
- D.The table title
Show the worked solution ▾
Answer: B. Drug A
- Step 1: Read Drug A: Drug A is 4 ng/mL.
- Step 2: Compare limit: Under 5 is negative; 4 is below 5.
Why it's right: Drug A is below its listed reference limit.
- A: The control checks validity.
- C: Drug B is 18 with positive cutoff 10.
- D: Title is not a substance.
Aligned to Biotechnology Research and Experiments · reading level ~grade 9
A screening result reads 0.8 mg/L and the cutoff on the report is written as 500 ng/mL. What has to happen before the result is called?
Reviewed- A.Discard the sample, because two different units can never be compared
- B.Report it negative, because 0.8 is a smaller number than 500
- C.Convert to one unit: 0.8 mg/L equals 800 ng/mL, which sits above 500
- D.Report it positive, because milligrams are always bigger than nanograms
Show the worked solution ▾
Answer: C. Convert to one unit: 0.8 mg/L equals 800 ng/mL, which sits above 500
- Step 1: Put both on one scale: 1 mg/L is 1 microgram per mL, which is 1000 ng/mL.
- Step 2: Convert the sample: 0.8 mg/L is 0.8 times 1000, which is 800 ng/mL.
- Step 3: Compare: 800 ng/mL is above the 500 ng/mL cutoff.
Why it's right: 0.8 mg/L converts to 800 ng/mL, which is above the 500 ng/mL cutoff. Numbers can only be compared once they are on the same scale.
- A: Units can always be converted, and converting is exactly what this result needs.
- B: Comparing 0.8 with 500 compares two different scales, so the comparison is meaningless.
- D: The right call here is positive, but not because of the unit names; it is because 800 exceeds 500.
Aligned to Biotechnology Research and Experiments · reading level ~grade 10
- In Unit 1.2 Master the Morgue, this skill turns class evidence into a result another person can check.
Fill these in as you work through the lesson.
- Toxicology (testing for drugs, poisons, or chemicals):
- Cutoff (value used to call positive or negative):
- Control (known check that test worked):
- Positive result (target is at or above the cutoff):
A toxicology result is interpreted by comparing the sample value to the and checking whether the worked.
- What is the sample value?
- What is the cutoff?
- Did the control behave as expected?
Drug B is 18 ng/mL and cutoff is 10 ng/mL. Write the result and one limitation.