Specimen HandlingQuestion 76 of 100
Why must additive tubes be mixed by gentle inversion rather than shaking?
a.Shaking increases the vacuum inside the tube
b.Shaking dissolves the stopper lubricant into the specimen
c.Gentle inversion is required only for serum tubes
d.Shaking causes mechanical hemolysis and foaming that invalidate many tests
Explanation
Vigorous shaking shears red cells and creates foam, producing hemolysis that falsely raises potassium, LDH and AST and can prevent testing altogether. Gentle inversion distributes the additive without damaging cells and is required for every additive tube, not just serum tubes. Shaking has no effect on stopper lubricant or on the residual vacuum.
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