Specimen requirement

Adult patient:

Clotted blood tube (Serum gel separator clot activator tube)

Minimum blood volume: 5 mL

Paediatric clotted blood tube

Number of vials: 1

Minimum blood volume: 0.8 mL

Authorisation code required

No

24 Hr available service

No

Method

Liquid chromatography-tandem mass spectrometry

Reference interval

19.3 - 53.9 µM

(Source: Clin Chem 2001; 47 (12): 2150 - 2153)

Clinical indication

Investigation of carnitine-deficient states, either primary (due to decreased intake, impaired synthesis or impaired renal reabsorption) or secondary (due to organic acidaemias).

Severe carnitine deficiency may be associated with hypoglycaemia, myopathy or cardiomyopathy.

Result interpretation

Hypoglycaemia, muscle weakness and cardiomyopathy do not occur until the level is less than 10 µmol/L.

In carnitine deficiency secondary to organic acidaemias, there is a relatively greater reduction in free carnitine.

Measurement of uncertainty

See table.

Frequency of measurement

Weekly