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Test ID: Oxalate (spot urine)
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Oxalate (spot urine)
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Oxalate (spot urine)
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Useful For
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The investigation and monitoring of renal stone formers
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Method name and description
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Clinical information
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Oxalate is a poorly soluble anion and high concentrations of in the urine is a risk factor for the formation of renal calculi. A group of inherited diseases (primary hyperoxalurias) can result in elevated oxalate concentrations due to aberrant glyoxylate or glycerate metabolism.
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Specimen type / Specimen volume / Specimen container
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Specimen type: spot urine.
Specimen volume: 4 mL.
Specimen container: suitable plain urine collection container.
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Collection instructions / Special Precautions / Timing of collection
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Avoid intake of oxalate rich food, like spinach, chocolate, rhubarb, or oxalate precursors such as vitamin C (Ascorbic Acid) for at least 48 hours before collection. Pyridoxine is said to diminish oxaluria. The patient should be on usual fluid and food intake.
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Relevant clinical information to be provided
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Presenting clinical signs and symptoms
Any relevant medications
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Storage and transport instructions
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Transport Temperature: 2 - 30 °C.
Storage Temperature: -20°C after add the preservative for upto 7 days.
The sample should not be thawed till analysis.
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Specimen Rejection Criteria
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Insufficient specimen quantity.
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Biological reference intervals and clinical decision values
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Adults: Oxalate /Creatinine ratio: < 0.04 mmol/mmol creatinine
Children: Oxalate/Creatinine ratio:
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Age
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Oxalate/Creatinine Ratio (mmol/mmol creatinine)
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Infant - < 1 year
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0.004 – 0.09
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1 – 4 years
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0.004 – 0.07
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5 – 11 years
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0.003 – 0.07
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>12 years
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< 0.04
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Factors affecting test performance and result interpretation
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High levels of ascorbate (vitamin C) can lead to artefactual increases in oxalate
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Turnaround time / Days and times test performed / Specimen retention time
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Turnaround time: 5 working days.
Days and times test performed: Once a week.
Specimen retention time: 7 days.
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