Preferred Sample Type

Urine Oxalate

Suitable Specimen Types

  • Plain Spot Urine
  • 24 Hour Urine Plain
  • 24 Hour Urine (Acid Collection)
8 mL aliquot of 24hr urine

Specimen Transport

First Class Post

Sample Processing in Laboratory


Sample Preparation

If non-acidified collection, acidify promptly on receopt with HCl to pH less than 2. Aliquot sample of 24 hour collection into universal container. Store sample frozen. Note on request form date, volume and period of collection.

Turnaround Time

10 working days

Sample Stability

Store frozen

Urine Oxalate

General Information

Oxalate in urine may arise either as an end-product of the metabolism of ascorbic acid and amino acids (especially glycine) or from dietary sources (e.g. rhubarb, spinach, tea). Hyperoxaluria leads to the formation of highly insoluble calcium oxalate which has a tendency to precipitate out in the renal medulla and urine leading to urolithiasis.

There are two forms of primary hyperoxaluria. Type I hyperoxaluria is associated with an increase in urine glycolate caused by deficiency of the peroxisomal enzyme alanine : glyoxylate aminotransferase (AGT). Patients present in the first decade of life with recurrent calcium oxalate nephrolithiasis. Type II hyperoxaluria is associated with an increase in urine L-glyceric acid caused by deficiency of the cytosolic enzyme D-glycerate dehydrogenase. Survival of these patients appears to be better than those with type I hyperoxaluria.

Hyperoxaluria may also occur secondary to inflammatory bowel disease or malabsorption. This may be due to a reduction in the levels of calcium in the gut, as the ionised calcium ion concentration is a limiting factor in oxalate absorption and low levels promote oxalate absorption.


Patient Preparation



From 10/05/2018, specimens sent to HSL, London for analysis.

NB: urine oxalate results now reported as umol/24hrs not mmol/24hrs

Reference Range

From 10/5/2018 refernce ranges will be:

100 - 460 umol/24 hour (adults, correct to 1.73m2for children)

Age related ref ranges for oxalate:creatinine ratio:

0-6 months  <291µmol/mmol

7-23 months  <220µmol/mmol

2-4 years  <143µmol/mmol

5-11 years  <76µmol/mmol

12 -17 years  <44µmol/mmol

18+ female    <45µmol/mmol

18+ male       <33µmol/mmol


  • EQA Scheme?: Yes
  • EQA Status: WEQAS

The laboratories at Heartlands Hospital, Good Hope Hospital and Solihull Hospital form part of the services provided by University Hospitals Birmingham and are UKAS (United Kingdom Accreditation Service) accredited to the ISO 15189:2012 standard. For a list of accredited tests and other information please visit the UKAS website using the following link:

  • Heartlands, Good Hope and Solihull Hospital pathology laboratories are a UKAS accredited medical laboratory No.8217
  • United Kingdom Health Security Agency laboratory is a UKAS accredited medical laboratory No.8213

Tests not appearing on the UKAS Schedule of Accreditation currently remain outside of our scope of accreditation. However, these tests have been validated to the same high standard as accredited tests and are performed by the same trained and competent staff.

For further test information, please visit the test database:

Protection of personal information - Laboratory Medicine comply with the Trust Data Protection policy and have procedures in place to allow the Directorate and its employees to comply with the Data Protection act  1998 and associated best practice and guidance.

For further information contact Louise Fallon, Quality Manager, 0121 424 1235