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Laboratory Medicine

Test Directory / Potassium


Brown clotted serum, gel barrier or orange lithium heparin

Common AbbreviationsK+, POT
ProfileUrea and Electrolytes
Tube typeBrown clotted serum, gel barrier or orange lithium heparin
Clinical IndicationMeasurement is used to identify hypo or hyperkalaemia. It may be used in the diagnosis and monitoring of kidney disease. It may also be requested in patients with diarrhoea and vomiting, excessive sweating, hypertension, metabolic acidosis or with symptoms that may be attributable to abnormal serum potassium levels (e.g. neuromuscular or cardiac abnormalities). Monitoring of potassium levels may also be indicated in patients taking certain medications (e.g. diuretics).
Specimen TypeBlood
Sample typeSerum or plasma
Minimum Volume0.5mL If requesting more than 10 tests please send an additional brown clotted serum sample.
Special PrecautionsNo special requirements
Stability2 weeks at 2 - 25°C
Turnaround TimeUrgent: 2 hours Inpatient: 4 hours Outpatient/ GP: 24 hours
LaboratoryYork and Scarborough
Reference Interval 3.5-5.3 mmol/L (Recommended by the Pathology Harmonisation Reference Group)
Limitations Old and haemolysed samples are unsuitable for analysis due to the release of intracellular potassium from red blood cells.
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Invitation to attend the Trust’s Annual Members Meeting

Trust members and the general public are invited to find out more about their local hospitals by attending the Trust’s virtual Annual Members Meeting (AMM), incorporating the Annual General Meeting (AGM), on Tuesday 26 October 2021, between 11:00am-12:30pm.