Blood free carnitine & acylcarnitines

Clinical Utility:

This tandem mass spectrometry (MSMS) semi-quantitative test is diagnostic for several fatty acids oxidation disorders, as well as branched-chain amino acids catabolism disorders. It is also useful in the determination of free carnitine in conditions caused by primary or secondary carnitine deficiencies. Disorders IDentified by MSMS

Specimen Types:

The most appropriate and convenient sample material is a dry blood spot. Blood can be obtained by a heel-prick from babies or finger-prick from older children and collected on Guthrie cards (provided by us). Blood collected in EDTA tube or heparin tube is acceptable from local hospitals. Plasma can also be used, but the quality of the data is not acceptable for long-chain acylcarnitines.

Turn-around Time:

Routine: 2-3 days from receipt of sample

Stat: 24 hours from receipt of sample

Test Limitations & Interfering Substances:

The results of this test do not include values for acylcarnitines. A value is provided for free carnitine if outside normal values. Antibiotics that are used as pivalate esters gives an interfering signal with that of C5-carnitine, which is the key metabolite for the diagnosis of isovaleric acidemia. In that case, confirmation by urine GC/MS analysis for organic acids is necessary.

Report Format:

The result is given in a one-page report that details the patient information, date of sample, date of analysis and a result code, which could be one of three:

"NOT REMARKABLE" "QUESTIONABLE" "ABNORMAL"

Interpretation of questionable or abnormal results will be provided. Recommendation for follow-up samples, or further tests, which are needed for confirmation, will be indicated.

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