Lab Procedures Flashcards

A PCT is about to perform venipuncture on a patient who has an IV infusing in the left arm. What is the best action?

Answer: Draw from the right arm

Drawing from the arm opposite the IV site prevents IV fluid from diluting the specimen and producing inaccurate results.

Which color tube top is used for a complete blood count (CBC)?

Answer: Lavender (purple)

Lavender/purple tubes contain EDTA, which prevents clotting and preserves blood cells for hematological analysis.

A rapid strep test is negative but the patient's symptoms strongly suggest strep throat. What should the PCT do?

Answer: Inform the nurse, as a throat culture may be needed for confirmation

Rapid strep tests have a false-negative rate; a negative result with high clinical suspicion warrants a confirmatory throat culture.

When labeling a blood specimen tube, the PCT should:

Answer: Label tubes at the bedside immediately after collection

Labeling at the bedside immediately after collection prevents specimen mix-ups, a critical patient safety requirement.

A urine dipstick test shows positive nitrites. This finding most likely indicates:

Answer: Bacterial infection in the urinary tract

Nitrites are produced when gram-negative bacteria convert urinary nitrates, making a positive result a strong indicator of UTI.

What is the maximum recommended time a tourniquet should remain in place during venipuncture?

Answer: 1 minute

A tourniquet left on longer than one minute causes hemoconcentration, which can falsely elevate many analyte levels.

Which specimen transport condition is required for an arterial blood gas (ABG) sample?

Answer: Placed in an ice slurry and analyzed within 30 minutes

Ice slurry slows cellular metabolism in the sample, preventing changes in pH, PO2, and PCO2 before analysis.