Urinary Organic Acids
Most organic acids are cleared efficiently by the kidney and
urine is used for screening.
Plasma is limited to monitoring methylmalonic acidaemias.
The circumstances under which samples 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).
Request on ICE
Analysed by referral laboratory if specific criteria met.
Requests must be accompanied by full clinical details and
information about any medication
The signs and symptoms will, to a large extent, determine the
tests requested and it is therefore VITAL to have adequate clinical
information. These tests may sometimes be URGENT as the disorder
may be life threatening, and close liaison with clinical staff is
Samples should be collected when the patient is unwell and
before treatment or a change in diet alters the pattern of
A fasting or pre-breakfast urine is required for investigation of
fatty acid oxidation defects.
5.0 ml in a white-capped universal
Sent to referral laboratory (Addenbrookes, Cambridge)
Samples should be transported to laboratory immediately.
Causes for Rejection
Not meeting specific criteria for analysis.
Delay in sample reaching laboratory
Reference range & interpretation
Qualitative results reported with interpretation