Synopsis
Interpret laboratory data through identity, specimen quality, method, reference context, biological variation and clinical probability, while acting safely on critical and changing results.
- Confirm patient, sample time, specimen type, units, reference interval and whether the result is final, corrected, point-of-care or laboratory generated.
- Ask why the test was ordered and what result was expected; an isolated flag is not a diagnosis and an unflagged result may still be dangerous.
- Check pre-analytical threats such as wrong tube, haemolysis, contamination, delay, posture, fasting, infusion sampling and recent treatment before explaining physiology.
Reasoning priorities
Check tube, collection site, timing, transport, haemolysis and laboratory comments.
A compromised specimen may require urgent clinical reassessment and a correctly collected repeat; it should not be silently averaged with valid results.
Worked reasoning
A clinically stable patient has potassium 6.8 mmol/L on a haemolysed sample, unchanged creatinine and a previous potassium of 4.2 mmol/L.
- Recognise potential immediate harm, move the patient to a monitored setting, obtain an urgent 12-lead ECG and start continuous rhythm monitoring. A normal ECG or unchanged creatinine does not exclude dangerous genuine severe hyperkalaemia.
- Check sample source, haemolysis comment, collection difficulty, infusion proximity, timing and linked analytes; the discordant stable renal indices make contamination or haemolysis plausible but not proven.
- Escalate immediately, contact the laboratory and obtain a correctly collected urgent paired repeat; a rapidly available blood-gas potassium can guide action while formal laboratory confirmation is pending when locally validated and appropriate.
- If potassium is confirmed at 6.5 mmol/L or above, or severe hyperkalaemia is strongly suspected, start the current UK Kidney Association severe-hyperkalaemia pathway without waiting for ECG changes. If paired testing proves artefact, avoid unnecessary ongoing treatment; document the resolution and monitoring plan.