Investigations for the diagnosis of an IEM
| First line investigations |
| Full blood count |
| Urea and electrolytes |
| Anion gap |
| Blood gases |
| Glucose |
| Lactate |
| Ammonia |
| Liver function tests |
| Urine reducing substances |
| Urine ketones |
| CSF lactate |
| Second line investigations |
| Urine organic acids |
| Urine amino acids |
| Plasma uric acid |
| Plasma amino acids |
| Plasma carnitine and acylcarnitine profile |
| Biotinidase |
| Galactosaemia screening tests (e.g. Beutler) |
| CSF amino acids |
| Third line or specialised investigations |
| Enzyme assays on skin fibroblasts or blood cells |
| DNA mutation analysis |
| Special metabolite assays (e.g. VLCFA, transferrin isoelectric focusing, etc) |