The Hemolyzed Chemistry Panel
A 45-year-old woman in the outpatient clinic has a chemistry panel ordered. The phlebotomist draws into a serum separator tube using a 23-gauge butterfly from a small hand vein. The draw is slow, and the tube is only half filled. The specimen is transported at room temperature and centrifuged two hours later. The resulting serum is visibly pink. The analyzer reports potassium 6.2 mmol/L, lactate dehydrogenase 480 U/L, and aspartate aminotransferase 95 U/L, while the patient's previous values were potassium 4.1, LDH 180, and AST 22. The physician calls the laboratory asking whether to send the patient to the emergency department.
1. How should the laboratory use the hemolysis index and the pattern of results to advise the physician?
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The visibly pink serum and the pattern of elevated potassium, LDH, and AST together are classic for in vitro hemolysis, not necessarily in vivo disease. Hemolysis releases potassium and LDH from red cells and can raise AST. The laboratory should check the hemolysis index reported by the analyzer and compare it with the validated threshold for each analyte. If the index exceeds the threshold, the potassium and LDH results should be suppressed or reported with a comment rather than released as actionable values. The laboratory should advise the physician that these results are likely artifactual, recommend a recollected specimen, and avoid an unnecessary emergency visit. If the patient has symptoms suggesting true hemolysis, such as anemia or jaundice, that should be evaluated separately, but the current pattern is most consistent with a preanalytical problem.
2. What collection changes would reduce recurrence, and how would you verify they worked?
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The draw used a small-gauge needle in a fragile vein, a partially filled tube, and delayed centrifugation, all of which increase hemolysis. The laboratory should recommend a larger-gauge needle where feasible, avoid excessive suction with a butterfly, fill tubes to the indicated volume, and centrifuge and separate serum promptly. For difficult draws, use a syringe and transfer technique that minimizes shear. The laboratory should track hemolysis index rates by collector and by draw site, re-educate on the specific steps, and re-audit after two weeks. A decrease in the proportion of hemolyzed specimens and in repeat draws would confirm improvement. The physician should also be told which analytes are most affected so future results are interpreted with the index in mind.