Collection ProceduresQuestion 14 of 100

During a capillary collection the phlebotomist must fill a lavender microtube and a serum microtube. Which order is correct?

a.Serum microtube first, then lavender
b.Lavender microtube first, then serum
c.Either order, because capillary blood has no additive carryover
d.Both must be filled at the same time from separate punctures

Explanation

The capillary order of draw differs from venipuncture: after any blood gas specimen, EDTA is collected first so that platelets are captured before they aggregate at the puncture site, followed by other additive tubes and finally serum. Filling the serum tube first would leave a clumped, unrepresentative platelet count. Carryover and clotting both occur in capillary work, so order does matter and a second puncture is not required.

Law Reference: CLSI GP42

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