Turnaround times
The quoted turnaround time is from sample receipt in the laboratory, to results authorisation in the Laboratory Information Management system. The times do not include transport of specimen to the laboratory or the administrative process to print and post/email reports. Service users must allow for transport and reporting time when ordering tests.
Clinical background:
Diagnosis / investigation of hypokalaemia
Specimen container paediatric:
Plain universal container (random urine sample)
Specimen container adult:
Plain universal container (random urine sample) or plain bottle (24 hour urine collection)
Minimum volume paediatric:
1 mL aliquot
Minimum volume adult:
1 mL aliquot
Sample stability:
7 days at 15-25°C,
7 days at 2-8°C,
1 year at -20°C
Interpretation:
Daily 24 hr urinary potassium excretion is dependent on daily intake, extra renal losses and intracellular shifts. Unless the dietary intake is known the 24 h urinary potassium is of little value.
Urine potassium should be interpreted in combination with the serum potassium concentration.
In the presence of hypokalaemia a random spot urine potassium of >20mmol/L indicates a renal potassium loss, values < 20 mmol/L indicate an extrarenal cause for the potassium depletion.
Reference ranges:
Adult: 25 – 125 mmol/24h
Factors affecting result:
Diet affects 24h potassium excretion