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Laboratory Procedures and Specimen Collection Flashcards

7 cards from real CMT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Laboratory Procedures and Specimen Collection flashcards as text

  1. Which evacuated tube color is used for coagulation studies such as PT and PTT?

    Answer: Light blue

    Light blue (sodium citrate) tubes are used for coagulation studies because citrate binds calcium to prevent clotting while preserving clotting factor activity.

  2. According to the CLSI order of draw, which tube should be collected FIRST when multiple tubes are needed?

    Answer: Blood culture bottles

    Blood culture bottles are drawn first to minimize the risk of contamination from skin flora and additives in other tubes.

  3. A tourniquet should be applied no longer than how many minutes before venipuncture to prevent hemoconcentration?

    Answer: 1 minute

    A tourniquet left on longer than 1 minute causes hemoconcentration and falsely elevated results for proteins, enzymes, and cellular components.

  4. Which of the following actions is the MOST common cause of hemolysis during venipuncture?

    Answer: Mixing tubes too vigorously

    Vigorous mixing of tubes breaks red blood cell membranes, releasing intracellular contents and causing hemolysis that can interfere with test results.

  5. A capillary puncture on an adult finger should be performed on which part of the fingertip?

    Answer: Side of the middle or ring finger

    The lateral (side) aspect of the middle or ring finger is the preferred site because it has adequate capillary beds and avoids nerves and bone centrally located in the fingertip.

  6. Which tube additive prevents glycolysis and preserves glucose levels in a specimen?

    Answer: Sodium fluoride/potassium oxalate

    Sodium fluoride inhibits the enzyme enolase to stop glycolysis, while potassium oxalate acts as an anticoagulant, making this tube the standard choice for glucose testing.

  7. When collecting a blood culture, the venipuncture site should be cleaned with:

    Answer: Chlorhexidine gluconate or iodine tincture after an initial alcohol scrub

    Blood cultures require a two-step disinfection — an initial 70% alcohol scrub followed by chlorhexidine gluconate or iodine tincture — to achieve maximum reduction in skin flora contamination.