MLPAO - Medical Laboratory Professionals Association of Ontario Specimen Collection and Handling Questions and Answers

Question 1

An MLA/T is tasked with collecting blood for coagulation studies (light blue top), a complete blood count (lavender top), and a basic metabolic panel (serum separator tube - SST). To prevent additive cross-contamination, what is the correct order of draw?

Accepted Answer

Light blue top, SST, Lavender top

Answer

The correct order of draw is based on CLSI guidelines to prevent contamination of specimens by additives from other tubes. The sequence is: 1) Blood cultures, 2) Sodium Citrate (light blue top) for coagulation, 3) Serum tubes with or without clot activator/gel (SST), 4) Heparin (green top), 5) EDTA (lavender top), and 6) Glycolytic inhibitor (gray top). Following this order ensures that the citrate tube for coagulation is drawn before tubes with clot activators or other additives that could interfere with testing.

Question 2

A physician's office sends a urine specimen for culture and sensitivity to the laboratory. Upon receipt, the MLA/T notices the specimen is in a non-sterile container. What is the most appropriate action?

Accepted Answer

Reject the specimen and request a new sample collected in the proper container.

Answer

Microbiology specimens for culture must be collected in sterile containers to prevent the introduction of environmental bacteria, which would lead to inaccurate results. A non-sterile container compromises the specimen's integrity, making it unacceptable for culture. The proper procedure is to reject the specimen and notify the provider to collect a new, valid sample.

Question 3

Which of the following analytes requires the specimen to be protected from light during collection and transport?

Accepted Answer

Bilirubin

Answer

Bilirubin is a light-sensitive analyte. Exposure to light, especially UV and fluorescent light, causes it to degrade rapidly, leading to falsely low results. Therefore, specimens for bilirubin testing must be collected in amber-colored tubes or wrapped in foil to protect them from light.

Question 4

An MLA/T receives a blood specimen for a Prothrombin Time (PT) test in a light blue top tube. The MLA/T observes that the tube is only filled to 50% of its capacity. What is the implication of this short draw?

Accepted Answer

The results will be falsely prolonged (higher).

Answer

Light blue (sodium citrate) tubes used for coagulation testing require a specific 9:1 blood-to-anticoagulant ratio. An underfilled tube contains an excess of the citrate anticoagulant relative to the amount of blood, which will bind more calcium than necessary and lead to falsely prolonged clotting times for tests like PT and aPTT.

Question 5

When collecting a specimen for forensic toxicology testing, what is the most critical procedure that must be meticulously followed to ensure the specimen is admissible in legal proceedings?

Accepted Answer

Maintaining a strict chain of custody.

Answer

Chain of custody is the chronological documentation or paper trail, showing the seizure, custody, control, transfer, analysis, and disposition of physical or electronic evidence. For forensic and legal testing, a meticulously maintained chain of custody is essential to prove that the specimen has not been tampered with and to ensure its integrity from collection to reporting.

MLPAO - Medical Laboratory Professionals Association of Ontario Practice Test

MLPAO - Medical Laboratory Professionals Association of Ontario Practice Test

MLPAO - Medical Laboratory Professionals Association of Ontario Specimen Collection and Handling Questions and Answers