Final answer:
For a skin puncture to test for WBC, RBC, glucose, and electrolytes, the color of the tubes used will depend on the specific tests ordered. Commonly, lavender tubes are used for CBC, gray tubes for glucose testing, and green tubes for electrolytes, but microcollection tubes specific to skin punctures will vary according to the laboratory's protocols.
Step-by-step explanation:
When a phlebotomist is unable to find accessible veins for venipuncture and it is deemed acceptable to perform a skin puncture, the color of the tube used for collecting a blood sample for WBC, RBC, glucose, and electrolyte tests will depend on the specific requirements of the tests ordered. For a complete blood count (CBC) that includes a hematocrit measurement to determine the percentage of RBCs, typically a lavender or purple tube containing EDTA is used. For glucose testing, a gray tube containing sodium fluoride is common.
Electrolyte measurements typically require a green-topped tube that contains heparin. However, when collecting blood via skin puncture (capillary blood), microcollection tubes or capillary tubes are used and these may have different color-coding specific to the collecting facility. The lab conducting the tests can provide the specific tubes and the corresponding color-coding required for these tests. It is important to follow the laboratory’s specific protocol and use the correct tubes for the specified tests.