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 CBPE exam has 100 questions and runs 6 hours.
These 10 free CBPE questions are organized by exam domain, so you can see how each part of the Certified Bloodstain Pattern Analyst (CBPA) blueprint is tested. Reveal the answer and explanation under each question.
A heavily bloodstained fabric yields a concentrated red extract with a positive Kastle-Meyer screen. A HemaTrace card shows only its control band at the specified reading time; external controls are acceptable. The laboratory has validated dilution procedures for concentrated extracts. Which next step addresses a possible cause of the negative card result?
Correct answer: A - Test a diluted aliquot on a new card using the validated procedure.
A laboratory removes most leukocytes from human blood to prepare a red-cell suspension. Dried samples produce a strong hemoglobin-based screening reaction but yield little nuclear DNA. Which explanation reconciles the results?
Correct answer: B - The screen detects hemoglobin; most nuclear DNA comes from the removed leukocytes.
While packaging a bloodstained glass fragment, an analyst is punctured through a glove. The analyst has completed hepatitis B vaccination, and a colleague can secure the evidence. Which response takes priority?
Correct answer: B - Wash immediately with soap and water, then report promptly for exposure evaluation.
In one continuous stroke, an initially clean swab is drawn through wet blood on a glass plate and then across adjacent clean glass. The original deposit is disturbed; the previously clean area receives a contact smear. Identify the patterns produced in those two areas, respectively.
Correct answer: C - Wipe, then swipe
High-speed video shows droplets flung from a blood-bearing rod as it sweeps through an arc at steady speed. The rod then strikes a stop. Those already released droplets reach the target after the rod has stopped. The resulting stains are best classified as:
Correct answer: C - Cast-off pattern
A stationary clean-water leak drips into a shallow pool of liquid blood in a sink. Each arriving water drop ejects smaller blood-bearing droplets from the pool. Under SWGSTAIN terminology, what is the most specific classification of the resulting pattern?
Correct answer: D - Drip pattern
A signed report interprets a blood flow using the photographed orientation of a removable panel and the stated assumption that the panel had not moved. Before testimony, a timestamped recording establishes that the panel was rotated after the blood dried and before the photographs were taken. The original stain measurements remain reliable. How should the analyst address this evidence?
Correct answer: D - Reassess the orientation-dependent conclusions and document any resulting report changes.
A bloody contact impression overlaps a group of airborne bloodstains on a door. One swab crossing both produces a two-person DNA mixture. Separately located, untested portions of each pattern remain. To investigate which donor contributed to which pattern, the analyst should:
Correct answer: D - Sample nonoverlapping portions of each pattern separately and record each sample location.
An isolated spatter stain on smooth tile has an elliptical body 5.0 mm long and 3.0 mm wide. Its narrow tail extends another 2.5 mm beyond the body. The estimated impact angle relative to the tile is closest to:
Correct answer: B - 37°
An original close-up shows a suitable elliptical spatter stain with a clearly resolved body on a flat, nonabsorbent surface. The camera was perpendicular to the surface, and the image has no perspective distortion or unequal resizing of its axes. No scale or object of known size is present. What quantitative information can still be obtained?
Correct answer: A - Estimated impact angle from the body’s pixel ratio, without physical stain dimensions.
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