Pathology Handbook

Non Jo-1 Synthetase Antibodies

Clinical Indications

(specialist request only)

Dermatomyositis Polymyositis

Please note: Jo-1 antibodies are found in 20-40% of patients with myositis. The non Jo-1 Synthetase antibodies are found in 5-10% of adult patients with myositis, PL-7 being seen in approximately 5% and PL-12 in 3%. The other antibodies are less common. The primary assay for Polymyositis or Dermatomyositis is the ENA screen which includes Jo-1 (histidyl tRNA synthetase).

Test Includes

Detection of autoantibodies to a family of aminoacyl-tRNA synthetases including PL-7 (threonyl tRNA synthetase); PL-12 (alanyl tRNA synthetase); EJ (glycyl tRNA synthetase) and OJ (isoleucyl tRNA synthetase).

Request Form 

Request via ICE.


Assay performed as required.

Specific Criteria

It is essential to provide relevant clinical information.

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. The assay is performed as required.


Serum in red top tube

Gold top (SST) tube will be accepted


7 ml


Vacutainer red top


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

A qualitative result is given and samples are reported as Positive, Weak Positive or Negative.