• Acetylcholine receptor (AChR)-binding antibodies
• Acetylcholine Receptor (AChR)-blocking antibodies
• Acetylcholine Receptor (AChR)-modulating antibodies
• Striational antibodies

Reflex criteria:

If Acetylcholine Receptor (AChR)-binding, blocking and modulating antibodies are normal, will reflex to Muscle Specific Kinase (MuSK) Antibodies performed at Esoterix Endocrinology Laboratory.

Tests for the laboratory diagnosis of myasthenia gravis (MG).

In rare cases AChR antibodies can be found in patients with other autoimmune disorders or with thymoma without MG.1

The causative autoantibody cannot be identified in up to 10 percent of patients with MG.

No isotopes administered 24 hours prior to sample collection

Red serum vial/tube, 10 mL

1. Allow sample to clot for a minimum of 30 to 60 minutes
2. Spin within two (2) hours of sample collection
3. Transfer 4.0 mL serum into two (2) a Transfer vial/tube with cap - 12mL (LabCorp), labelled as serum

Transfer vial/tube with cap - 12mL (LabCorp)

Gold serum separator (SST) tube x 3

Immediately following collection, mix sample by gently inverting 5 times

1. Allow sample to clot for a minimum of 30 to 60 minutes
2. Spin within two (2) hours of sample collection

Refrigerated (preferred) - 14 days

Ambient - 7 days

Frozen - 14 days

• Excessive hemolysis
• Chylous serum
• Recently administered radioisotopes
• Plasma specimen

AChR Binding Abs, Serum  nmol/L 

 Negative: 0.00 - 0.24

 Borderline: 0.25 - 0.40

 Positive: >0.40

AChR Blocking Abs, Serum  % 

 Negative: 0 - 25

 Borderline: 26 - 30

 Positive: >30

AChR Modulating Abs, Serum  % 

 Negative: 0 - 45

 Positive: >45

Striation Abs, Serum   Negative

If MuSK Abs reflex: 

  Negative: <1.0;   Positive: 1.0 or higher

Acetylcholine receptor autoantibodies are not typically found in congenital myasthenia gravis