Red cells contain far more potassium than plasma, so haemolysis falsely raises serum potassium, and also lactate dehydrogenase, AST and phosphate. A high potassium on a visibly or index-flagged haemolysed sample should not be acted on as if it were real.
Report the haemolysis index with the result, suppress or annotate affected analytes according to your laboratory's thresholds, and ask for a repeat sample when the result would change management.
- Haemolysis falsely raises potassium, LDH, AST and phosphate.
- Annotate or suppress affected results according to local haemolysis-index thresholds.
- Phone a high potassium on a haemolysed sample with a request to repeat.
- Track haemolysis rates by collection site to target training.
Why it matters
A falsely raised potassium can trigger treatment or delay a discharge for a value that was never in the patient.
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