The Effects of Storage Temperature and Time on Serum Potassium Level

Proper specimen storage is compulsory to avoid inaccurate laboratory results, wrong diagnosis and repeated sampling in patients. Electrolyte tests are usually performed as regular check-ups for specific medical conditions, such as decreased renal function, heart failure, and diarrhoea. Potassium is the main intracellular cation, which is important for regulating heart function and maintaining healthy nerves and muscles. This study was carried out to evaluate the effects of storage temperature and time on serum potassium levels among apparently healthy individuals. The consent of 12 participants was sought and obtained before enrolment. Chemchek Agappe potassium kits was used in ICuBio Ichaem-535 Chemistry Analyser to determine serum potassium level at different time interval and storage temperatures. The serum samples were analysed immediately after collection (control), 1 hour, 2hours, 4 hours, 24hours, 48hours, and 72hours at storage conditions of 4oC and -25oC simultaneously. Data were analysed using SPSS version 16. Test of probability less than 0.05(p<0.05) was regarded as significant. There was no significant difference (p>0.05) in the K serum level of samples stored at 4oC from 1hr to 4hrs when compared with the control. There was no significant difference (p>0.05) in the K serum level of samples stored at -25oC from 1hr to 48hrs when compared with the control. There was a significant difference (p<0.05) in the serum K level of samples stored up to 24hrs and 72hrs at 4oC and -25oC respectively. In conclusion, storing serum samples for K determination at 4oC and -25oC for a maximum of 4hrs and 48 hrs respectively gives a stable, reliable and reproducible result. However, storage for up to 24hrs and 72 hours at 4oC and -25oC respectively gives a significantly unstable, unreliable and inaccurate result.