Information checked 24 October 2026. General information, not individual medical advice.
Does a haemolysed sample mean my high potassium is not real?
Not necessarily. Haemolysis can interfere with potassium measurement, but a genuinely high potassium result can be dangerous. Do not dismiss a result or postpone a requested repeat because the report mentions a sample problem. Contact the requesting team and follow its instructions about timing and where to be assessed. [1,2]
What haemolysis means in a sample
Red blood cells can break down in the collected sample, releasing their contents. NHS laboratory guidance identifies difficult collection, prolonged tourniquet use, fist clenching, storage conditions and delay before analysis among possible causes of a falsely raised potassium. A sample issue is not the same as a diagnosis of a disease destroying blood cells inside your body. The laboratory and clinician need to distinguish these situations. [1]
Why the repeat is not just administration
Potassium is involved in normal muscle and heart function. NHS Highland guidance distinguishes mild, moderate and severe elevations and considers the result alongside symptoms, kidney function, medicines and the speed of change. More severe results or concerning circumstances can require urgent hospital assessment. An online explanation cannot set a safe waiting time for your individual result. [2]
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What the team may need to check
The clinician may compare previous results, review kidney function and medicines, speak with the laboratory and arrange an appropriately collected repeat. Some cases require an ECG or urgent assessment. Do not try to correct the result with supplements, restrictive diets or changes to prescribed medicine on your own. The same number can require different action in different circumstances. [1,2]
Questions worth asking immediately
Ask: Has the laboratory been able to report potassium reliably? When and where must I repeat the sample? Who will receive the new result? Should I be assessed today? What should I do if I feel worse? If you cannot reach the requesting team, use an urgent medical service rather than assuming silence means the result is safe.
What to tell the person collecting the repeat
Tell the collector that this is a repeat after a haemolysed or unexpected potassium result and provide the original report if available. Let the clinical team decide which specimen and handling arrangements are needed. NHS laboratory guidance sets out specific collection and processing approaches; these are not instructions for you to collect or transport a clinical specimen without an agreed route. [1]
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Symptoms should override a routine booking plan
If you have severe symptoms such as collapse, chest pain or severe breathlessness, seek emergency help. Otherwise follow the urgency given by the clinician for the result, even if you feel well. A dangerous potassium level does not have to announce itself with obvious symptoms before it needs attention. [2]
A result-review service should close the loop
For a private blood-test enquiry with The Online GP by The Wellness, ask who reviews results, how urgent findings are communicated and how repeats are arranged. If a result has already been flagged urgent, say so at the start. A routine appointment request is not a substitute for urgent assessment.
Sources
- NHS Lothian laboratory medicine, pseudohyperkalaemia guidance
- NHS Highland, hyperkalaemia in primary care
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