Anti-Microsomal Antibody
(AMA)

Sample type:

serum

Uses:

The measurement of autoantibodies against thyroid peroxidase is useful in identifying patients with autoimmune thyroid disease

Precaution:

• Analysis should not be performed on haemolysed, icteric or lipaemic samples. The assay is unaffected by biotin < 40.9 nmol/L or < 10 ng/mL.

• No interference was observed from rheumatoid factors up to a concentration of 1350 IU/mL.

• Samples should not be taken from patients receiving therapy with high biotin doses (i.e. > 5 mg/day) until at least 8 hours following the last biotin administration.

Interference:

In vitro tests were performed on 16 commonly used pharmaceuticals; no interference with the assay was found. In addition special drugs were tested; no interference with the assay was found. In rare cases, high titres of antibodies to analyte specific antibodies, streptavidin or ruthenium can occur.

Pre analytical error:

Sample collection:

Venipuncture should be performed in the most atraumatic way as possible since a good sample collection technique is vital to obtain a blood sample of adequate quality for analysis.

Sample storage:

Haematology samples should be processed and examined as soon as possible, ideally within a few hours for collection. If the sample is sent to an external laboratory, refrigeration is recommended.

Corrective action

Supervision of the analytical process very carefully, using state of the art analysers and having in place a daily internal quality control system and an external quality programme for most measured analytes.

Post analytical errors:

• Processing of results for transcription onto report forms

• Reduce human error through root-cause analysis, process control, and education/communication

Reference range:

<35 IU/mL.