Plasma
Urine
Fluid
Adult patient:
Heparin gel tube
Minimum blood volume: 5 mL
Spot urine:
Plain bottle
Minimum volume: 10 mL
24 Hr urine:
U4 bottle
Plain bottle
Minimum volume: 10 mL
Paediatric patient:
Paediatric heparin tube
Number of vials: 1
Minimum blood volume: 1.3 mL
Authorisation code required
No
24 Hr available service
Yes
(Call extension: 3353 for express result)
No
No
Method
Spectrophotometry
Reference interval
Plasma:
| Female: | 0.17 – 0.36 mmol/L |
| Male: | 0.25 – 0.52 mmol/L |
(Source: from local population study in 2008)
Female during pregnancy:
| 13 - 20 weeks | 0.11 - 0.27 mmol/L |
| 21 - 28 weeks | 0.12 - 0.30 mmol/L |
| 29 - 34 weeks | 0.12 - 0.33 mmol/L |
| 35 - 42 weeks | 0.15 - 0.39 mmol/L |
| During active labour | 0.17 - 0.44 mmol/L |
| Day 1 postpartum | 0.19 - 0.45 mmol/L |
| 0.19 - 0.46 mmol/L |
(Source: Klajnbard A et al. Laboratory Reference Intervals during Pregnancy, Delivery and the Early Postpartum Period. Clin Chem Lab Med. 2010 Feb; 48(2): 237 - 48.)
Urine:
1.5 - 4.4 mmol/d
(Source: Roberts WL et al. Reference Information for the Clinical Laboratory. In Tietz Textbook of Clinical Chemistry and Molecular Diagnostics, 4th edn. Burtis CA, Ashwood ER and Bruns DE eds. Elsevier Sanuders 2006; 2251 - 2318)
Clinical indication
Plasma:
Diagnosis and monitoring of gout
Monitoring of therapy in malignancies where there is a high rate of cell destruction and uric acid production.
Urine:
Gout, renal calculous disease, suspected Lesch-Nyhan syndrome
Result interpretation
Plasma:
The likelihood of gout is low if the serum urate concentration is repeatedly below 0.42 mmol/L. The risk of developing gout is three times greater if the serum urate concentration is consistently above 0.42 mmol/L. However, a raised serum urate level alone is insufficient to diagnose gout.
Impaired renal function, pregnancy-induced hypertension, diuretics, fasting, hyperlactataemia, hyperketonaemia and low dose salicylates can all produce increased urate levels.
Hypouricaemia is seen in patients with a low purine intake, in SIADH, with hypouricaemic drugs (e.g. allopurinol) and in the rare condition of xanthinuria.
Urine:
Patients with a high urate excretion have an increased risk of forming
uric acid renal calculi.
Urine urate excretion is influenced by diet. Increased levels are obtained on a high carbohydrate low protein diet. Values less than 10 mmol/d can properly be considered normal unless a specific diet has been prescribed.
Measurement of uncertainty
Ascorbic acid < 30 mg/dL does not interfere.
Frequency of measurement
Daily