Collection ProceduresQuestion 24 of 100
A patient is told to pump the fist repeatedly while the tourniquet is on. Which result is most affected?
a.Hemoglobin, which may be falsely decreased
b.Potassium, which may be falsely elevated
c.Sodium, which may be falsely decreased
d.Platelet count, which may be falsely elevated
Explanation
Vigorous fist pumping causes muscle cells to release potassium into the local circulation, so the measured potassium can be falsely high. Patients may make a fist once to help the vein, but repeated pumping is discouraged. Hemoglobin, sodium and platelet counts are not meaningfully changed by this mechanism.
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