Venipuncture and Phlebotomy Flashcards

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

Answer: 21 gauge

A 21-gauge needle is the standard choice, balancing adequate flow with patient comfort.

What complication results from drawing blood too quickly or with too small a needle, damaging red cells?

Answer: Hemolysis

Hemolysis is the rupture of red blood cells, which can falsely elevate potassium and other analytes.

A bruise that forms at the puncture site due to blood leaking into surrounding tissue is called a:

Answer: Hematoma

A hematoma forms when blood escapes the vein into nearby tissue, often from a needle passing through the vein.

Which tube additive is the anticoagulant of choice for coagulation studies such as PT and PTT?

Answer: Sodium citrate

Sodium citrate in the light blue top tube is used for coagulation testing because it reversibly binds calcium.

What is the correct blood-to-additive ratio that must be maintained in a sodium citrate tube?

Answer: 9 parts blood to 1 part additive

Coagulation tubes require a 9:1 blood-to-citrate ratio for accurate results, so they must be filled completely.

Before performing a venipuncture, what is the most important step to ensure correct specimen labeling?

Answer: Verify patient identity using two identifiers

Using two patient identifiers prevents specimen mislabeling and serious patient safety errors.

If a vein cannot be felt in either arm, what is an acceptable alternative site for venipuncture?

Answer: Veins on the dorsal (back) of the hand

Hand veins are an acceptable alternative, usually requiring a smaller gauge needle or butterfly set.