Laboratory Procedures Flashcards

A fasting blood glucose level of 126 mg/dL or higher on two separate occasions indicates:

Answer: Diabetes mellitus

Per ADA criteria, a fasting blood glucose of 126 mg/dL or higher confirmed on two occasions meets the diagnostic threshold for diabetes mellitus.

When collecting a clean-catch midstream urine specimen, the patient should:

Answer: Clean the urethral meatus, discard initial flow, then collect midstream

Clean-catch midstream technique cleans the urethral area, discards the initial stream (which flushes urethral contaminants), then collects midstream urine for accurate culture results.

The hemoglobin A1C test measures:

Answer: Average blood glucose over the preceding 2–3 months

HbA1c reflects the percentage of hemoglobin glycated over the lifespan of red blood cells (~120 days), providing a 2–3 month average blood glucose estimate.

In a complete blood count (CBC), a differential WBC count identifies:

Answer: The percentage and type of each white blood cell in the sample

The differential count classifies leukocytes into five types (neutrophils, lymphocytes, monocytes, eosinophils, basophils) and reports each as a percentage of total WBCs.

Which color-coded evacuated tube top is used for coagulation studies (PT/INR, aPTT)?

Answer: Light blue (sodium citrate)

Light blue-top tubes contain sodium citrate anticoagulant and must be filled exactly to the line to maintain the 9:1 blood-to-anticoagulant ratio required for accurate coagulation testing.

A urine dipstick positive for both nitrites and leukocyte esterase most likely indicates:

Answer: Urinary tract infection (UTI)

Nitrites (produced by bacteria converting urinary nitrates) combined with leukocyte esterase (released by WBCs) strongly suggest bacterial urinary tract infection.