Laboratory Procedures Flashcards

The order of draw for venipuncture using evacuated tubes begins with:

Answer: Blood culture bottles

Blood culture bottles are drawn first to prevent contamination from tube additives. CLSI order: blood cultures → light blue → red/gold → green → lavender → gray.

When performing a finger-stick capillary blood collection, the best site on an adult is:

Answer: The lateral tip of the ring or middle finger

The lateral side of the ring or middle finger has adequate capillary blood flow, less nerve density, and avoids the sensitive fingertip center, minimizing discomfort.

A point-of-care (POC) INR test would be ordered to monitor therapy with which medication?

Answer: Warfarin (Coumadin)

INR (International Normalized Ratio) measures standardized prothrombin time and is used to monitor warfarin anticoagulation therapy.

The Gram stain procedure classifies bacteria based on:

Answer: Cell wall composition — gram-positive retain crystal violet; gram-negative do not

Gram-positive bacteria have thick peptidoglycan walls that retain crystal violet and appear purple. Gram-negative bacteria have thin peptidoglycan and appear pink/red after the safranin counterstain.

Which condition is indicated by a urine specific gravity of 1.035?

Answer: Concentrated urine / possible dehydration

Normal urine specific gravity is 1.005–1.030. A value of 1.035 indicates highly concentrated urine, suggesting dehydration or inadequate fluid intake.

The term 'CLIA-waived' for a laboratory test means:

Answer: The test is simple, accurate, and poses minimal patient risk — and can be performed without complex lab certification

CLIA-waived tests are FDA-cleared, simple to perform, and have a low risk of error. Medical assistants can perform them in physician office labs with a certificate of waiver.