SOUTH CAROLINA LAW ENFORCEMENT DIVISION CRIME LAB EXAM – PRACTICE QUESTIONS AND
CORRECT ANSWERS (VERIFIED ANSWERS) PLUS RATIONALES 2026 Q&A | INSTANT DOWNLOAD PDF.
*Core Domains*
*Evidence Collection and Chain of Custody*
*Forensic Biology and DNA Analysis*
*Drug Chemistry and Toxicology*
*Firearms and Toolmark Identification*
*Latent Print Development*
*Trace Evidence Analysis*
*Quality Assurance and Ethics*
*Legal Testimony and Procedures*
*Introduction*
*The South Carolina Law Enforcement Division (SLED) Crime Lab Exam is a comprehensive assessment
designed to evaluate the proficiency and readiness of forensic professionals. This exam
targets the critical knowledge required to maintain the integrity of physical evidence
while applying advanced scientific methodologies. Candidates are assessed on a wide range
of skills, including foundational laboratory theories, stringent regulatory compliance,
and the ethical considerations inherent in criminal investigations. Through a combination
of multiple-choice and complex scenario-based questions, the exam emphasizes real-world
application and analytical decision-making. Success ensures that practitioners can
provide defensible, high-quality forensic results that uphold the standards of the
justice system.*
SECTION ONE: QUESTIONS 1–100
1. Which of the following is the primary purpose of maintaining a strict chain of custody for physical evidence?
,A. To identify the manufacturer of the evidence collection kit
B. To provide a continuous record of possession and handling
C. To ensure the evidence is stored in a temperature-controlled environment
D. To simplify the process of laboratory intake
🟢 B. To provide a continuous record of possession and handling
🔴 RATIONALE: The chain of custody is a legal requirement that documents every individual who had contact
with the evidence, ensuring its integrity and admissibility in court.
2. In forensic DNA analysis, what is the specific role of Polymerase Chain Reaction (PCR)?
A. To determine the biological sex of the contributor
B. To measure the exact age of a biological stain
C. To amplify small or degraded amounts of DNA into workable quantities
D. To provide a visual image of the DNA helix
🟢 C. To amplify small or degraded amounts of DNA into workable quantities
🔴 RATIONALE: PCR allows forensic scientists to create millions of copies of specific DNA sequences, which is
essential when only trace amounts of biological material are recovered.
3. Which chemical reagent is most commonly used for the preliminary identification of blood at a crime scene
based on a peroxidase-like activity?
A. Ninhydrin
B. Amido Black
C. Phenolphthalein (Kastle-Meyer test)
D. Silver Nitrate
,🟢 C. Phenolphthalein (Kastle-Meyer test)
🔴 RATIONALE: Phenolphthalein reacts with the hemoglobin in blood to produce a pink color change, serving as
a presumptive test for the presence of blood.
4. A technician encounters a firearm with a jammed slide at a crime scene. What is the first priority?
A. Photograph the serial number
B. Place the firearm in a plastic bag immediately
C. Render the firearm safe without altering its forensic condition more than necessary
D. Disassemble the firearm completely for transport
🟢 C. Render the firearm safe without altering its forensic condition more than necessary
🔴 RATIONALE: Safety is the paramount concern in evidence recovery; the firearm must be cleared to prevent
accidental discharge while preserving potential trace evidence.
5. In toxicology, the term "LD50" refers to:
A. The legal dose limit for a controlled substance
B. The dose required to produce a response in 50% of the population
C. The dose that is lethal to 50% of a test population
D. The duration it takes for 50% of a drug to leave the bloodstream
🟢 C. The dose that is lethal to 50% of a test population
🔴 RATIONALE: LD50 stands for "Lethal Dose, 50%," a standard measure used to compare the acute toxicity of
different substances.
, 6. Which fingerprint pattern is characterized by ridges entering from one side, rising in the center, and exiting
on the opposite side?
A. Loop
B. Whorl
C. Plain Arch
D. Tented Arch
🟢 C. Plain Arch
🔴 RATIONALE: A plain arch is the simplest fingerprint pattern and does not possess deltas, cores, or significant
upward thrusts like the tented arch.
7. What is the standard methodology used by latent print examiners to reach a conclusion regarding an
identification?
A. HPLC-MS
B. ACE-V
C. SWGFAST-D
D. STR Analysis
🟢 B. ACE-V
🔴 RATIONALE: ACE-V stands for Analysis, Comparison, Evaluation, and Verification, which is the scientific
method used for the examination of friction ridge skin impressions.
8. When collecting liquid blood evidence from a crime scene that cannot be immediately refrigerated, what is
the preferred method of preservation?
CORRECT ANSWERS (VERIFIED ANSWERS) PLUS RATIONALES 2026 Q&A | INSTANT DOWNLOAD PDF.
*Core Domains*
*Evidence Collection and Chain of Custody*
*Forensic Biology and DNA Analysis*
*Drug Chemistry and Toxicology*
*Firearms and Toolmark Identification*
*Latent Print Development*
*Trace Evidence Analysis*
*Quality Assurance and Ethics*
*Legal Testimony and Procedures*
*Introduction*
*The South Carolina Law Enforcement Division (SLED) Crime Lab Exam is a comprehensive assessment
designed to evaluate the proficiency and readiness of forensic professionals. This exam
targets the critical knowledge required to maintain the integrity of physical evidence
while applying advanced scientific methodologies. Candidates are assessed on a wide range
of skills, including foundational laboratory theories, stringent regulatory compliance,
and the ethical considerations inherent in criminal investigations. Through a combination
of multiple-choice and complex scenario-based questions, the exam emphasizes real-world
application and analytical decision-making. Success ensures that practitioners can
provide defensible, high-quality forensic results that uphold the standards of the
justice system.*
SECTION ONE: QUESTIONS 1–100
1. Which of the following is the primary purpose of maintaining a strict chain of custody for physical evidence?
,A. To identify the manufacturer of the evidence collection kit
B. To provide a continuous record of possession and handling
C. To ensure the evidence is stored in a temperature-controlled environment
D. To simplify the process of laboratory intake
🟢 B. To provide a continuous record of possession and handling
🔴 RATIONALE: The chain of custody is a legal requirement that documents every individual who had contact
with the evidence, ensuring its integrity and admissibility in court.
2. In forensic DNA analysis, what is the specific role of Polymerase Chain Reaction (PCR)?
A. To determine the biological sex of the contributor
B. To measure the exact age of a biological stain
C. To amplify small or degraded amounts of DNA into workable quantities
D. To provide a visual image of the DNA helix
🟢 C. To amplify small or degraded amounts of DNA into workable quantities
🔴 RATIONALE: PCR allows forensic scientists to create millions of copies of specific DNA sequences, which is
essential when only trace amounts of biological material are recovered.
3. Which chemical reagent is most commonly used for the preliminary identification of blood at a crime scene
based on a peroxidase-like activity?
A. Ninhydrin
B. Amido Black
C. Phenolphthalein (Kastle-Meyer test)
D. Silver Nitrate
,🟢 C. Phenolphthalein (Kastle-Meyer test)
🔴 RATIONALE: Phenolphthalein reacts with the hemoglobin in blood to produce a pink color change, serving as
a presumptive test for the presence of blood.
4. A technician encounters a firearm with a jammed slide at a crime scene. What is the first priority?
A. Photograph the serial number
B. Place the firearm in a plastic bag immediately
C. Render the firearm safe without altering its forensic condition more than necessary
D. Disassemble the firearm completely for transport
🟢 C. Render the firearm safe without altering its forensic condition more than necessary
🔴 RATIONALE: Safety is the paramount concern in evidence recovery; the firearm must be cleared to prevent
accidental discharge while preserving potential trace evidence.
5. In toxicology, the term "LD50" refers to:
A. The legal dose limit for a controlled substance
B. The dose required to produce a response in 50% of the population
C. The dose that is lethal to 50% of a test population
D. The duration it takes for 50% of a drug to leave the bloodstream
🟢 C. The dose that is lethal to 50% of a test population
🔴 RATIONALE: LD50 stands for "Lethal Dose, 50%," a standard measure used to compare the acute toxicity of
different substances.
, 6. Which fingerprint pattern is characterized by ridges entering from one side, rising in the center, and exiting
on the opposite side?
A. Loop
B. Whorl
C. Plain Arch
D. Tented Arch
🟢 C. Plain Arch
🔴 RATIONALE: A plain arch is the simplest fingerprint pattern and does not possess deltas, cores, or significant
upward thrusts like the tented arch.
7. What is the standard methodology used by latent print examiners to reach a conclusion regarding an
identification?
A. HPLC-MS
B. ACE-V
C. SWGFAST-D
D. STR Analysis
🟢 B. ACE-V
🔴 RATIONALE: ACE-V stands for Analysis, Comparison, Evaluation, and Verification, which is the scientific
method used for the examination of friction ridge skin impressions.
8. When collecting liquid blood evidence from a crime scene that cannot be immediately refrigerated, what is
the preferred method of preservation?
