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:
Sodium is the major extracellular cation in the body and along with its associated anions, contributes to most of the plasma osmolality and therefore plays an important role in water and electrolyte homeostasis. The amount of sodium in the body is a reflection of the balance between sodium intake and output. The body requires only 1 to 2 mmol/day, and the excess is excreted by the kidneys. Measurement of sodium in urine provides an indication of sodium balance, and whether sodium loss is of renal or extra-renal origin, e.g. gastrointestinal loss.
Specimen container paediatric:
Plain universal container
Specimen container adult:
Plain universal container (randome sample), plain bottle for 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
Quality assurance:
WEQAS
Interpretation:
Urine sodium excretion varies with dietary intake.
In hypervolaemic states, urine sodium <10 mmol/L indicates extra-renal loss of sodium, e.g. vomiting/diarrhea; urine sodium >20 mmol/L indicates renal sodium loss, e.g. diuretics, osmotic diuresis, mineralocorticoid insufficiency.
In hypervolaemic states, urine sodium <10 mmol/L indicates nephrotic syndrome, liver cirrhosis and congestive heart failure; urine sodium >20 mmol/L indicates renal failure.
Reference ranges:
24 hour urine collection:
Male:
6 – <10 years: 41 – 115 mmol/24h
10 – 14 years: 63 – 177 mmol/24h
Female:
6 – <10 years: 20 – 69 mmol/24h
10 – 14 years: 48 – 168 mmol/24h
Male and female:
>14 years: 40 – 220 mmol/24h
Other info:
Acid rinsed bottle acceptable