Lactate:pyruvate ratio in CSF and plasma
| Category | Biochemistry |
|---|---|
| Test background |
Measurement of plasma lactate may be indicated in children presenting with myopathy or neurological signs. A child with a persistently elevated lactate level, not explained by causes such as hypoxia, poor perfusion/shock, fits or liver disease, should be investigated for inborn metabolic disorders. In neurological disorders, lactic acidosis may be confined to the CNS without systemic acidosis and the measurement of CSF lactate is useful. A relatively low pyruvate with a raised lactate (lactate:pyruvate ratio >25) is suggestive of pyruvate carboxylase deficiency or respiratory chain defects. |
| Clinical Indications |
A child with a persistently elevated lactate level not explained by causes such as hypoxia, poor perfusion/shock, fits or liver disease. |
| Reference range | See report |
| Sample & container required | Pyruvate is an unstable intermediate. Samples for lactate:pyruvate ratio must be deproteinised on collection according to the protocol of the referral laboratory. |
| Sample volume | See protocol |
| Turnaround time | Up to 6 weeks |
| Notes | Not currently performed in house; this is a referred test. |