| Specimen requirement | Spot urine: Plain urine bottle Minimum volume: 3 mL |
| Authorisation code required | No |
| 24 Hr available service | No |
| Precaution | Relevant information (including patient’s information, clinical presentation, biochemical abnormalities, diet, and treatment) must be provided either by an information sheet for metabolic screening, or data entered into the GCRS system. |
| Method | Gas chromatography mass spectrometry (GCMS) |
| Reference interval | See result interpretation section. |
| Clinical indication | Identification of the cause of metabolic acidosis with increased anion gap in an infant or child if an organic acidaemia is suspected. Diagnosis of certain genetic diseases in which abnormal organic acids occur without metabolic acidosis. |
| Result interpretation |
In some diseases the abnormality is present only intermittently (e.g. during metabolic acidosis). The nature and relative amount of organic acids detected usually allows the complete identification of the type of organic acidaemia present and at least narrows it down to a relatively small group. Abnormal organic acids are often seen in non-genetic lactic acidosis and ketoacidosis and careful interpretation is required. Results interpreted by medical and scientific staff specialised in the field of inherited metabolic diseases. |
| Measurement of uncertainty | See table. |
| Frequency of measurement | Weekly |