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PTD - 272

Test Directory -  Urinary Organic Acids

Clinical Indications

Most organic acids are cleared efficiently by the kidney and urine is used for screening. Plasma is limited to monitoring methylmalonic acidaemias.

Analysis of organic acids in urine can assist in the diagnosis of a number of
disorders including those of amino acid metabolism (e.g. MSUD, urea cycle

Request Form 

Combined Pathology Blood form (Yellow/Black or Blue for GP's) and Metabolic screening questionnaire


Analysed by referral laboratory if specific criteria met.

Specific Criteria

Requests must be accompanied by a completed Metabolic screening questionnaire which has been authorised by a Consultant.

Patient Preparation

Samples should be collected when the patient is unwell and before treatment or a change in diet alters the pattern of metabolites.

A fasting or pre-breakfast urine is required for investigation of fatty acid oxidation defects.


The circumstances under which a sample is collected is of critical importance since in cases of an incomplete metabolic block, characteristic metabolites may only be detected at times of metabolic decompensation (e.g. infection).

Turnaround Time

2 weeks




5.0 ml


White Capped Universal

Samples should be transported to laboratory immediately.

Causes for Rejection

Unlabelled sample.
Not meeting specific criteria for analysis. 
Delay in sample reaching laboratory

Lab. Handling

Processing: Freeze primary sample at -20C in separating freezer (CB40).
Referral: UORGA and send or NOUOA and save in separating freezer (CB40) at -20C.


Version 1.0 / July 2014                                                                                                          Approved by: Consultant Biochemist