10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
The ABC-BIO exam has 60 questions and runs 1 hours 30 minutes.
These 10 free ABC-BIO questions are organized by exam domain, so you can see how each part of the Biological Evidence Screening blueprint is tested. Reveal the answer and explanation under each question.
In a sequential Kastle-Meyer test, a swabbing from a cleaned tile turns pink when reduced phenolphthalein reagent is added, before the addition of 3% hydrogen peroxide. The pink color deepens after peroxide is added. The known-blood control and reagent blank respond correctly. The result from the swabbing is:
Correct answer: C - Inconclusive: the color appeared before peroxide was added.
A stain on a nursing bra gives a positive RSID-Saliva result at the specified reading time, with acceptable controls. The wearer was breastfeeding. An investigator asks whether this establishes oral contact with the tested area. Which response is supported by the assay findings?
Correct answer: B - Breast milk can supply the detected alpha-amylase; oral contact is not established.
An extract from a stained condom contains no spermatozoa on microscopy but gives valid positive PSA and semenogelin tests. Which anatomical pairing explains how the protein findings can coexist with the microscopic result?
Correct answer: A - PSA: prostate; semenogelin: seminal vesicles.
On a Christmas-tree-stained slide from an aged vaginal swab, an examiner finds multiple structures satisfying the laboratory's sperm-head identification criteria. No attached tails are present, and staining controls are acceptable. A reviewer questions whether tail absence defeats the identification. What is the appropriate interpretation?
Correct answer: B - Sperm are identified; loss of tails does not negate the supported head identification.
An amplification requires 0.90 ng of DNA in no more than 5.0 microliters of extract. For quantitation, 10 microliters of the original extract was mixed with 40 microliters of buffer; the diluted aliquot measures 0.12 ng/microliter. Both preparations are suitable for amplification. Select the addition that meets both requirements.
Correct answer: B - 1.5 microliters of the original extract.
Screening of a vaginal swab from a sexual-assault kit gives a valid negative acid phosphatase result, and no spermatozoa are found on microscopy. Little material remains. The case priority is to investigate a possible male DNA contributor, and DNA testing is authorized. What is the best use of the remainder?
Correct answer: A - Submit the remaining swab material directly for the authorized DNA examination.
Two pipettes set to 50.0 microliters undergo repeated delivery checks. Pipette A has a mean delivery of 47.5 microliters and a standard deviation of 0.10 microliters. Pipette B has a mean of 50.1 microliters and a standard deviation of 1.20 microliters. Compared with B, pipette A is:
Correct answer: D - More precise, with a mean farther from the set volume.
While opening a tube, an examiner splashes liquid containing human blood into one eye. An eyewash is immediately accessible. Which action takes priority?
Correct answer: D - Begin flushing the exposed eye with water at the eyewash.
After a LIMS report-template update, a valid negative result, an unexamined sample, and a test with a failed positive control all print as "No blood detected." The stored result codes are correct. The template has been repaired. Before release, the most direct check of that repair is to:
Correct answer: C - Check each result-code mapping by comparing its generated report with the expected interpretation.
A presumptive blood test has been evaluated on white cotton. Before extending its use to dark denim, the laboratory needs to determine whether the dye can mimic the endpoint or mask a true reaction. Which experiment addresses both concerns?
Correct answer: C - Test a range of known bloodstains on denim alongside matching unstained denim through the complete procedure.
The ABC-BIO exam also covers these domains. Drill them in the full free practice test:
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