Free NHA Laboratory Procedures and Specimen Handling Questions and Answers — Questions and Answers
Question 1: What is the correct order of draw for a light blue top tube, a lavender top tube, and a serum separator tube (SST)?
- Lavender, SST, Light Blue
- SST, Lavender, Light Blue
- Light Blue, SST, Lavender (Correct answer)
- Light Blue, Lavender, SST
Correct answer: Light Blue, SST, Lavender
The standard order of draw prevents additive cross-contamination. Coagulation tubes (light blue) are drawn first, followed by serum tubes like the SST, and then tubes with other additives like EDTA (lavender).
Question 2: The additive in a lavender-topped collection tube is:
- Sodium Citrate
- Heparin
- EDTA (Correct answer)
- No additive
Correct answer: EDTA
Lavender (or purple) top tubes contain the anticoagulant Ethylenediaminetetraacetic acid (EDTA). EDTA works by binding to calcium in the blood, which prevents the clotting cascade from occurring and preserves blood cell morphology for hematology tests.
Question 3: Which type of urine specimen is required for a culture and sensitivity test?
- Random specimen
- First-morning specimen
- 24-hour specimen
- Clean-catch midstream specimen (Correct answer)
Correct answer: Clean-catch midstream specimen
A clean-catch midstream specimen is necessary to minimize contamination from external bacteria. This ensures that any microorganisms grown in the culture are from the patient's urinary tract, leading to an accurate diagnosis.
Question 4: Which of the following is an example of a CLIA-waived test commonly performed in a medical office?
- Blood culture analysis
- Urine pregnancy test (Correct answer)
- Pap smear analysis
- Complete blood count (CBC) with differential
Correct answer: Urine pregnancy test
CLIA-waived tests are simple procedures with a low risk of an incorrect result. A rapid urine pregnancy test is a prime example of a waived test that medical assistants are trained to perform.
Question 5: What is the most critical step in ensuring the accuracy of a laboratory result?
- Using the correct vacuum tube
- Properly labeling the specimen (Correct answer)
- Centrifuging the specimen at the correct speed
- Transporting the specimen to the lab quickly
Correct answer: Properly labeling the specimen
Properly identifying the patient and correctly labeling the specimen at the time of collection is the most critical step. A mislabeled or unlabeled specimen can lead to a catastrophic error in diagnosis and treatment.
Question 6: When preparing a blood specimen for transport to an outside laboratory, what action should the medical assistant take?
- Freeze the specimen immediately
- Place the specimen in a regular paper envelope
- Complete a requisition and place it in the outer pocket of the transport bag (Correct answer)
- Leave the specimen unlabeled until it arrives at the lab
Correct answer: Complete a requisition and place it in the outer pocket of the transport bag
The specimen must be placed in a biohazard transport bag, and the completed laboratory requisition form should be placed in the bag's outer pocket. This keeps the form clean and dry while ensuring all necessary information travels with the specimen.
Free NHA Laboratory Procedures and Specimen Handling Questions and Answers
What is the correct order of draw for a light blue top tube, a lavender top tube, and a serum separator tube (SST)?