National Healthcareer Association Flashcards

A gray-top tube contains which additives and is primarily used for which test?

Answer: Sodium fluoride and potassium oxalate; glucose/lactate testing

Gray-top tubes contain sodium fluoride (glycolysis inhibitor) and potassium oxalate (anticoagulant), making them ideal for glucose and lactate testing.

When performing a venipuncture, the bevel of the needle should be positioned:

Answer: Facing up (bevel up) at a 15–30° angle

Inserting the needle bevel-up at 15–30° allows smooth vein entry and reduces patient discomfort.

Which of the following is an example of a pre-analytical error that could affect blood test results?

Answer: Patient not fasting before a lipid panel blood draw

Pre-analytical errors occur before analysis; failing to fast before a lipid panel introduces dietary lipids that falsely elevate triglycerides.

A phlebotomist notices a patient is diaphoretic and complaining of dizziness during blood collection. The BEST immediate action is:

Answer: Remove the needle, apply pressure, and have the patient lie down

Signs of vasovagal syncope require stopping the procedure immediately and positioning the patient to prevent injury from fainting.

According to CLSI guidelines, which tube is drawn LAST in a multi-tube venipuncture order of draw?

Answer: Gray-top (sodium fluoride/oxalate)

Per CLSI order of draw, gray-top tubes are collected last to prevent additive carryover from affecting other tests.

What is the purpose of inverting tubes immediately after blood collection?

Answer: To mix the blood with the additive and prevent clotting or ensure proper preservation

Gentle inversion ensures thorough mixing of blood with the tube's additive, preventing clot formation in anticoagulant tubes or activating clotting in SST tubes.

Which needle gauge is most commonly used for routine adult venipuncture?

Answer: 21-gauge

A 21-gauge needle is the standard for adult venipuncture, balancing adequate blood flow with minimal patient discomfort.