Phlebotomy

Standard venous order of draw: blood cultures, light blue (sodium citrate), serum/red or SST, green (heparin), lavender (EDTA), then gray (sodium fluoride).

Blood cultures are drawn first to maintain sterility and prevent contamination.

Lavender (EDTA) is for hematology such as CBC; green (heparin) for plasma chemistry; gray (sodium fluoride) preserves glucose and lactate.

A plain red tube has no additive and yields serum after clotting; an SST (gold/tiger) contains a clot activator and gel separator.

Following the correct order of draw prevents additive carryover that alters results.

Insert the needle at a 15-30 degree angle with the bevel up during venipuncture.

The median cubital vein is usually the first choice; the cephalic is a second choice, and the basilic is used with caution near the brachial artery and nerves.

Leave the tourniquet on no longer than 1 minute to prevent hemoconcentration; release it once blood flow is established.

Verify the patient with two identifiers before collecting any specimen.

Perform infant heel sticks on the medial or lateral plantar surface of the heel to avoid the bone (calcaneus).

Capillary order of draw differs: collect blood gases first, then EDTA (hematology), then other additive tubes, then serum.

Collect EDTA early in a capillary draw to obtain an adequate, well-mixed hematology sample before clotting begins.

Wipe away the first drop of a capillary specimen when indicated, as it may be contaminated with tissue fluid.

Gently invert additive tubes the recommended number of times immediately after collection; never shake, which causes hemolysis.

Hemolysis can falsely elevate results such as potassium; avoid vigorous shaking, too-small needles, and prolonged tourniquet time.

Label tubes at the bedside immediately after collection in the patient's presence, including name, identifiers, date, time, and collector's initials.

Confirm and document fasting status (typically 8-12 hours) for fasting tests and report non-fasting patients to the nurse or provider.