Pathology Handbook

Acetylcholine Receptor Antibodies

Synonyms

ACR ACH receptors AChR

Clinical Indications

Myasthenia Gravis

Ocular Myasthenia

Please note: As the antibodies are IgG, they can cross the placenta and cause neonatal myasthenia. Low level antibodies may be seen in ocular myasthenia. The highest levels are seen in young patients (<40 years with generalised disease) while lower levels are seen in older patients, those with thymoma and in penicillamine induced myasthenia. Approximately 10% of typical myasthenic patients are negative for Acetylcholine receptor antibodies. Patients with ocular Myasthenia Gravis may be seronegative. Antibodies persist in 60% of patients even if the disease is in remission.

Test Includes

Detection of IgG antibodies against acetycholine receptors

Request Form 

Request via ICE

Availability

Assay performed weekly

Specific Criteria

It is essential to provide relevant clinical information, especially whether the patient is pregnant.

Patient Preparation

No special preparation is required.

Turnaround Time

All samples are generally sent to referral laboratory within 3 working days of receipt in the laboratory. Samples are batched and the assay is performed once per week.

Specimen

Serum in red top tube.

Gold top (SST) tube will be accepted

Volume

7 ml

Container

Vacutainer red top

Collection

Samples should be transported to the laboratory as soon as is practicably possible.

Lab. Handling

Aliquot and store at 4-8°C prior to testing and at -20°C or below for up to 1 month after receipt.

Causes for Rejection

Unlabelled/inadequately labelled sample.

Inadequately completed request form.

Delay in sample reaching laboratory.

Reference Range

0 -0.45 nmol/litre

Levels above 0.45 nmol/litre are regarded as POSITIVE.