Peripheral Venous Blood Sampling

ContraindicationsTop

As in IV injections (see Intravenous Injections).

Potential ComplicationsTop

Phlebitis, hematoma, infection.

Patient Preparation and Venipuncture SiteTop

As in IV injections.

EquipmentTop

As in IV injections. However, special vacuum tubes or syringes with matching needles are most frequently used instead of standard needles and syringes. The contents of tubes or syringes used for blood sample collection as well as the label or cap color code vary depending on the planned tests; if unsure, check with the nursing staff or your laboratory to ensure you are using the correct tube types:

1) Empty tubes or tubes containing a coagulant (dry tube; “clot tube”) are used for measurements of electrolytes, urea, creatinine, bilirubin, lipids, enzymes, and other serum proteins.

2) Tubes containing ethylenediaminetetraacetic acid (EDTA) or heparin are used for complete blood count (CBC).

3) Tubes containing sodium citrate are used for plasma coagulation tests, that is, international normalized ratio (INR), activated partial thromboplastin time (aPTT), fibrinogen, and D-dimer levels. The usual citrate salt to blood sample volume ratio is 1:9.

4) Tubes containing sodium fluoride are used for plasma glucose.

5) Tubes containing lithium heparin are used for serum ammonia or whole blood electrolyte levels.

ProcedureTop

As in IV injections (see Intravenous Injections). In some blood collection systems a special needle is introduced into the vein and a vacuum tube or syringe is connected after blood appears in the needle hub. If many different tests are necessary, the needle is left in the vein while various tubes or syringes are being attached.