Maybe Is a Result

One presumptive test report

Make one presumptive test report, Parts A–E. Use the handout for your class's case. You will interpret four supplied stain records, explain what their results cannot establish, and account for the classroom test allowances.

Complete one presumptive test report, Parts A–E. Hand the paper report to Mr. Mendoza before leaving, or submit one PDF to this section's Schoology assignment by September 17 at 11:59 PM. Use your period and investigator code. Do not submit the same report twice; keep notebook pages in your notebook.

Supplied illustrative case record. These are supplied illustrative case records, not observations you made. Photo labels and coordinates are reported references, not photographs or measurements you independently examined. No individual color or timing observations are supplied for these four rows.

Your Case A D08 assignment · Daily directions

Five steps

1. Open your case's handout. Add your period and investigator code. Label your work “Supplied illustrative case record.” Read R1–R6 and answer A1–A2.
2. Complete the four report cards for B1. Keep each evidence ID with its documentation, classification, missing observations, qualified wording, route and limit. F1 shows the record workflow; the separate kitchen model is available if useful.
3. Finish the negative log and budget, B2–B3. Use your case's explicitly named negative and its supplied numbers. Show the arithmetic and decide whether any reported positive must wait.
4. Write the short memo and vocabulary response, C1–D1. Explain each route with its evidence and allowance reason. A route does not supply a completed test result. Keep the four memo parts together.
5. Complete E1–E3, check and submit. Check all ten task IDs, all four stain IDs and your source labels. Turn in this one report on paper or as one PDF in your section's Schoology assignment.

One work sequence. Optional help explains the current task; it does not add a parallel work plan.

Keep notebook pages in your notebook. You may copy F1 and update a line in your evidence log as support; do not upload a second product.

Before you submit

I have four complete report cards, B2's negative log, B3's arithmetic, C1's four-part memo, D1 and all five short reading/self-check answers. A1–A2 and E1–E3 are those five short answers, not another product. Missing observations are labeled; the rust inference stays conditional. I have not claimed to view missing photos or identify a donor.

Hand the paper report to Mr. Mendoza before leaving, or submit one PDF in the assignment Wk4 D08 · Maybe Is a Result (PLTW 1.1.4). The online deadline is September 17 at 11:59 PM. Use your period and investigator code in the header. Do not submit the same work twice. Keep notebook pages in your notebook.

If you were absent or need help

Use the same supplied-record handout and complete the same report. You do not need to find missing specimens or make up colors, times or pictures. If your teacher supplies actual approved classroom observations, label that separate source and follow the assigned instructions; do not silently combine it with this practice record.

Lost your place? Find the next unanswered task ID. R2 supports the reading questions; R3 and F1 support the rows; R4–R5 support the budget and memo; R6 supports documentation. Guided notes and the kitchen model are support, not extra submissions. The existing preparation gate applies before any separate teacher-directed bench task, not as proof that this paper report completed one.

If your teacher is absent: Use the complete handout, R1–R6 and F1. Complete the paper-record report only. Do not begin an unassigned hands-on task.

R1 / R2. Reading

R1. Your job today

Complete one presumptive test report, Parts A–E. A presumptive test is an initial screen that can indicate a material may be present without identifying it. Serology is the study of blood and other body fluids. Today you analyze supplied illustrative records. You do not run a test, photograph a stain or identify a person.

Use only the four stain records for your class's case. The evidence ID identifies a row. The description, photo references and coordinates come from the supplied record. RP1 and RP2 mean reference point 1 and reference point 2; the distances are recorded in centimeters. Do not replace these with guessed room measurements.

R2. Why careful language matters

Some other materials, including fruits and oxidizing substances on a surface, can affect a chemical screen. An oxidizing substance can cause a chemical change that affects the screen's response. This does not identify the substance in any of our case stains. An expected classroom outcome is a prediction, not a recorded result. A stain's name does not establish that the testing process worked correctly. NIJ screening background [S1].

Calling an initial positive confirmed blood can send attention or a limited follow-up allowance toward an unsupported conclusion. Treating a negative as proof that nothing was present can cause relevant information to be dismissed. These are possible consequences, not measured error rates for this exercise. A reported negative means the material of interest was not detected by that screen; it does not establish its absence. NIST definition [S2].

R3 / R4. Reading

R3. Record the result and its limit

For a reported positive, use the case's qualified phrase: presumptive positive for blood; confirmatory testing required. For the explicitly reported negative, use no indication of blood by presumptive screen. These are the classroom report's labels, not guarantees of identification or absence.

If an observation is missing, write not reported in the supplied record. A missing observation is not a negative result or proof of test failure. Individual colors and times are not supplied for the four case rows. Do not invent them.

Rust needs a different status. Its individual observation is not reported. The aggregate summary lists two negative swabs, while only one is individually named. Use the permitted statement: Individual observation not reported; the summary implies a negative classification if its four-stain record is complete. An inference is a conclusion drawn from other information. Keep this inference conditional rather than calling it an observed negative.

R4. Use the classroom budget

For this paper exercise, each swab starts with two test allowances. Each recorded screen uses one allowance. Multiply swabs by allowances per swab, then subtract the recorded screens. The follow-up limit is a separate constraint. Compare that limit with the number of reported positives before deciding whether any must wait.

This is classroom accounting; it does not establish how much real material a test uses or whether a real sample can be tested again. Those decisions require the approved method and sample information. A route is the next step proposed or reported for an item, with a reason. “None waits” is a valid decision when the supplied numbers support it. Keep the kitchen example's different numbers out of your case report.

R5 / R6. Reading

R5. A route is not an identification result

The term confirmatory test is used in the original classroom record for further evaluation. It does not guarantee a definite answer. In this exercise, “confirmatory allowance” names a place in the follow-up budget, not a guarantee of identification. Further testing would need a stated question, an appropriate method, an actual result and its limits. Sending an item forward does not supply that result.

Today's records do not establish species, donor or time of deposition. A DNA comparison would be separate evidence; none is supplied here. The NIST report warns against categorical identification wording, and NIJ explains that DNA results require interpretation and suitable comparison information. NIST, §§4.6.2–4.6.3 [S3], NIJ DNA-result background [S4].

R6. Keep the documentation attached

Documentation preserves a record of an item's location and appearance before later work. Keeping its references beside its evidence ID lets another reader trace your statement to its source. The W and UV labels in this packet are supplied photo references, not pictures you examined. A reported pattern description is also a source statement, not your own image analysis.

Attribute the case's pattern descriptions and reported absences to that record. A pattern reported absent differs from one the record does not mention. The descriptions alone do not establish whether an event was a fall or an attack. The historical reporting draft separates source information, observations and conclusions; it does not validate this case. NIST-hosted 2017 draft, §§4.2.9–4.2.12 [S5].

PLTW connection and preparation

This John Hay original record exercise practices careful reporting, limited-resource reasoning and evidence limits connected to PLTW Activity 1.1.4, Blood Evidence, in Lesson 1.1, Investigating the Scene. It does not certify completion of the official activity. The retained PLTW activity link is supporting access, not an extra task for this report. If it does not open, the required explanation and records are here.

Before any separate teacher-directed hands-on task, complete the existing Kastle-Meyer preparation gate and follow your teacher's approved instructions. This paper report does not provide bench clearance or certify practical performance. No extra DNA simulation is required for the report.

Optional help

For A1–A2, use R2. For the four rows, use R3 and the F1 record workflow. For the budget and memo, use R4–R5 and the separate kitchen model. For a documentation question, use R6. Guided notes can help organize your thinking; they are not another submission. The explanation above contains the required background, so the source links are not an additional reading assignment.

Plain-English terms

Presumptive test

An initial screen that can indicate a material may be present without identifying it.

Serology

The study of blood and other body fluids.

Evidence ID

Identifies a row. The description, photo references and coordinates come from the supplied record.

RP1 and RP2

Reference point 1 and reference point 2; the distances are recorded in centimeters.

Oxidizing substance

Can cause a chemical change that affects the screen's response. This does not identify the substance in any of our case stains.

Reported negative

The material of interest was not detected by that screen; it does not establish its absence.

Not reported in the supplied record

The status to write when an observation is missing. A missing observation is not a negative result or proof of test failure.

Inference

A conclusion drawn from other information. Keep the rust inference conditional rather than calling it an observed negative.

Test allowance

For this paper exercise, each swab starts with two test allowances. Each recorded screen uses one allowance.

Route

The next step proposed or reported for an item, with a reason.

Confirmatory test

The term used in the original classroom record for further evaluation. It does not guarantee a definite answer.

Confirmatory allowance

A place in the follow-up budget, not a guarantee of identification.

Documentation

A record of an item's location and appearance before later work.

W and UV labels

Supplied photo references, not pictures you examined.

Complete the existing preparation gate before any separate teacher-directed hands-on task. This paper report does not grant bench clearance or certify practical performance.

No extra DNA simulation is required for the report.

If your teacher supplies actual approved classroom observations, label that separate source and follow the assigned instructions; do not silently combine it with this practice record.

K1. Separate kitchen practice report

Optional worked support. This is the existing illustrative kitchen example, not Case A or Case B. No part of this model is a new required submission or evidence for your assigned case.

A reddish smear is described on a wooden cutting board in a kitchen where someone reported a bad cut. The record has three swabs. It identifies photo C-01 for the cutting-board smear and mentions two location measurements, but supplies no numerical coordinates. C-01 is a listed reference, not a photograph shown here. The other descriptions are a brown spot on the sink rim and a red spot on the counter.

The supplied kitchen narrative classifies the cutting-board smear and counter spot as presumptive positives and the sink-rim spot as negative. Its colors are part of that illustrative narrative, not observations you made. This paper model uses its reported classifications. It gives no operating instructions and supplies no new result for your case.

A worked report row

Record

cutting-board smear, separate kitchen practice.

Documentation

the record names C-01 and says the location was documented. The two measurement values are not reported here.

Reported result

presumptive positive.

Qualified phrase

presumptive positive for blood; confirmatory testing required.

Recorded route and reason

the practice record sends this item forward because the surface was reportedly used by the injured person. That is the reason given in the record, not proof of the person's identity or where an injury occurred.

Limit

the referral supplies no follow-up result. Species, donor and time remain unestablished.

For the sink-rim spot, the model uses “no indication of blood by presumptive screen” and records that this example stops further routing for that item. It does not change the phrase to “no blood.” The counter spot retains the qualified positive phrase while waiting under this example's budget.

K1. Worked classroom accounting and memo

The kitchen example has three swabs and two allowances per swab:

• Starting allowances: 3 × 2 = 6.
• Recorded screens: 3. Remaining after screens: 6 − 3 = 3.
• Separate follow-up allowance: 1.
• Reported positives: 2. One can proceed under this limit; the other waits.

The remaining total allowance and the follow-up cap answer different questions. The example uses the one follow-up place for the cutting-board smear and leaves the counter spot waiting. This illustrates how a stated constraint affects a paper-record choice. It is not a universal rule about sample consumption.

Worked short memo

The separate kitchen record routes the cutting-board smear forward and leaves the counter spot waiting. Both are reported positives, but the practice budget allows only one follow-up. The source gives priority to the cutting board because it was reportedly used by the injured person; this is a stated reason, not proof of the event. Using that one allowance leaves no follow-up place for the counter spot now. Both records still need qualified positive language because no follow-up result is supplied.

Use the structure, not the answers

For your assigned report, return to your four own-case IDs, documentation references and budget. Your case has four swabs and two follow-up allowances. Decide from that record whether anything waits. Do not transfer C-01, the kitchen locations or the one-place limit into your case. F1 and R1–R6 provide the same report method without requiring a second example response.

F1. From a supplied record to a careful report

Find your case and evidence ID, then retain its documentation references. Check whether the record supplies an individual positive, an individual negative, a missing observation or a conditional inference. Do not collapse those four statuses into two. Copy the supported qualified phrase or state the missing item or inference. Next, check the classroom allowance record and explain a proposed route with an evidence reason, including whether any reported positive must wait. Finish by stating the limits. A route does not produce a new result or identify a donor.

The qualified positive phrase is “presumptive positive for blood; confirmatory testing required.” The qualified negative phrase is “no indication of blood by presumptive screen.” Both keep the limits explained in R3. The rust row keeps the exact conditional status provided in your case data.

Optional check

If two entries disagree, record the disagreement or missing information. Do not fill a gap with the other case, the kitchen example or an expected color. In this exercise, no new test is required to finish the report.

Help when you need it

Lost your place? Find the next unanswered task ID. Use R2 for Part A, R3 and F1 for B1, R4–R5 for B2–C1, and R6 for documentation. Keep working in the same report.

Case A. Supplied records 1–2

Supplied illustrative case record. These are supplied illustrative case records, not observations you made. Photo labels and coordinates are reported references, not photographs or measurements you independently examined. No individual color or timing observations are supplied for these four rows.

Setting: Statik Sound, a neighborhood recording studio. Case number JH-26-0831-A.

Case A. Supplied records 3–4

The summary does not individually name rust as the second negative. Keep its conditional inference separate from a reported individual result. Do not guess a color or time.

Case A. Routing, allowance and pattern records

The supplied summary reports that E2-console and E2-floor went forward under the two follow-up allowances and that no positive had to wait. It supplies no follow-up test result.

Negative log: E2-ctrl-soda: no indication of blood by presumptive screen. Photo W-21. Sample remaining: one test.

Classroom allowance record: 4 swabs, 2 allowances per swab, 4 recorded screens, 2 follow-up allowances, 2 reported positives.

The summary reports four screens, two swab halves reserved for follow-up, and two negative swabs retained with their untested halves kept in custody. This is a supplied classroom record, not a procedure to follow.

The two-allowances-per-swab rule is classroom accounting. It does not establish real sample consumption, compatibility or suitability for another test.

Pattern summary, as reported

The E3 documentation summary describes a contact smear at the console corner and passive drops on the floor below. It reports no cast-off pattern and no impact-spatter field. These are the source's descriptions, not an image analysis you performed. Its fall-versus-attack implications were recorded as questions only.

Qualified phrases from R3: presumptive positive for blood; confirmatory testing required; no indication of blood by presumptive screen.

Your Parts A–E presumptive test report

Case A, STATIC, Period 1-2. Investigator code, not name:

Record route label: Supplied illustrative case record, or a separately labeled teacher-approved actual classroom record.

Date: September 17, 2026

Complete Parts A–E in one report. Use your period and investigator code, not a name. Label the record route. Keep every evidence number beside its response. The supplied-record route is available to everyone.

PBS-U1-D08-A1

Name two kinds of material besides blood that the reading says can affect a screen. Copy the first three words of the sentence you used.

PBS-U1-D08-A2

Explain two reporting errors: treating an initial positive as confirmed blood, and treating a negative as proof that no blood was present. Give one possible consequence of each. Copy the first three words of a supporting sentence from R2.

B1. Report card 1 of 4

PBS-U1-D08-B1

Complete one report card for each of your case's four stain IDs. Record the documentation references, reported classification or missing-status statement, qualified result phrase or conditional inference, and proposed route with a reason. For color and time, use not reported when the record supplies none. Keep the rust inference conditional.

One card per stain ID. Keep the four cards together in the same report.

B1. Report card 2 of 4

PBS-U1-D08-B1

Complete one report card for each of your case's four stain IDs. Record the documentation references, reported classification or missing-status statement, qualified result phrase or conditional inference, and proposed route with a reason. For color and time, use not reported when the record supplies none. Keep the rust inference conditional.

One card per stain ID. Keep the four cards together in the same report.

B1. Report card 3 of 4

PBS-U1-D08-B1

Complete one report card for each of your case's four stain IDs. Record the documentation references, reported classification or missing-status statement, qualified result phrase or conditional inference, and proposed route with a reason. For color and time, use not reported when the record supplies none. Keep the rust inference conditional.

One card per stain ID. Keep the four cards together in the same report.

B1. Report card 4 of 4

PBS-U1-D08-B1

Complete one report card for each of your case's four stain IDs. Record the documentation references, reported classification or missing-status statement, qualified result phrase or conditional inference, and proposed route with a reason. For color and time, use not reported when the record supplies none. Keep the rust inference conditional.

One card per stain ID. Keep the four cards together in the same report.

B2/B3. Negative log and allowance budget

PBS-U1-D08-B2

Use your case's explicitly named negative stain, not rust. Write its evidence ID, qualified negative phrase, photo reference and remaining test allowance. Explain why the phrase does not prove that blood was absent.

PBS-U1-D08-B3

Show the classroom budget for four swabs with two test allowances each. Subtract the four recorded screens. Then use the two follow-up allowances and the two reported positive IDs to explain how many can proceed and whether any must wait. Keep the allowance calculation separate from a claim that a follow-up test succeeded.

Starting allowances: ___ × ___ = ___

After recorded screens: ___ − ___ = ___

Separate follow-up limit: ___

Reported positive IDs: ___

Can proceed: ___; must wait: ___

Reason and accounting limit: ___

C1. Routing-and-ethics memo

PBS-U1-D08-C1

Write one short routing-and-ethics memo with four parts: which reported positives can proceed and whether any must wait; an evidence reason for each proposed route; how the classroom allowance limit affects the choice; and the qualified wording that remains until further results are actually supplied. None waits is valid when the case supports it. Do not claim species, donor, time, or a completed follow-up result.

1. Proceed/wait decision

2. Evidence reasons

3. Allowance and ethics reason

4. Result wording and limits

D/E. Finish the same report

PBS-U1-D08-D1

Use confirmatory test and serology in one or two sentences about this paper-record exercise. Explain the follow-up role without claiming that it guarantees identification. A copied definition alone is not enough.

PBS-U1-D08-E1

A supplied record classifies a stain as a presumptive positive. Write the qualified report phrase. This is a reading check, not a new case result.

PBS-U1-D08-E2

A supplied record classifies a screen as negative. Does that prove the material was absent? Answer in one line with the limit.

PBS-U1-D08-E3

Why does the report keep the documentation made before testing? Give one reason, and do not claim to have viewed photographs that are only listed by reference.

I have four complete report cards, B2's negative log, B3's arithmetic, C1's four-part memo, D1 and all five short reading/self-check answers. A1–A2 and E1–E3 are those five short answers, not another product. Missing observations are labeled; the rust inference stays conditional. I have not claimed to view missing photos or identify a donor.

Optional notebook support

Keep notebook pages in your notebook. You may copy F1 and update a line in your evidence log as support; do not upload a second product.

Use this template only if helpful. It does not replace a required response or add another product.

One evidence log row

Date

Evidence ID

Supplied-record statement

Interpretation and limit

Report task ID

Cornell cues

1. What was reported?
2. What was not reported?
3. What can the budget support?

In one sentence, explain where a report must stop.

Optional vocabulary extra credit

The existing optional vocabulary extra credit may remain optional, separate from required D1. Use terms from this lesson and do not add a required submission.

Handoff, PLTW and sources

Complete one presumptive test report, Parts A–E. Hand the paper report to Mr. Mendoza before leaving, or submit one PDF to this section's Schoology assignment by September 17 at 11:59 PM. Use your period and investigator code. Do not submit the same report twice; keep notebook pages in your notebook.

Carry forward your evidence IDs, reported classifications and limits. A later lesson needs its own supplied evidence; today's report does not supply a DNA result.

This John Hay original record exercise practices careful reporting, limited-resource reasoning and evidence limits connected to PLTW Activity 1.1.4, Blood Evidence, in Lesson 1.1, Investigating the Scene. It does not certify completion of the official activity.

Local John Hay practice connected to the activity, not certification of official completion. The retained PLTW activity link is supporting access, not an extra task for this report. If it does not open, the required explanation and records are here.

Case A D08 assignment · Official PLTW section hub · Activity 1.1.4 Blood Evidence

Sources and optional background

• S1. NIJ screening background

  cited in R2.

• S2. NIST definition

  cited in R2.

• S3. NIST, §§4.6.2–4.6.3

  cited in R5.

• S4. NIJ DNA-result background

  cited in R5.

• S5. NIST-hosted 2017 draft, §§4.2.9–4.2.12

  cited in R6.

Today's records do not establish species, donor or time of deposition. A DNA comparison would be separate evidence; none is supplied here. A route does not produce a new result or identify a donor.