Myasthenia Gravis (MG) Lab Test
Myasthenia Gravis (MG) Lab Test can be requested without a referral, and this overview covers what to expect. The myasthenia gravis (MG) lab test is a blood test that looks for antibodies associated with MG, a condition that causes muscle weakness. It is ordered when a doctor suspects MG based on symptoms like drooping eyelids, double vision, or difficulty chewing, swallowing, or speaking.
- Sample type
- blood
- Category
- General Wellness
- Turnaround
- 1-3 business days
- Price
- $319
- Referral
- Not required
The myasthenia gravis (MG) lab test is a blood test that looks for antibodies associated with MG, a condition that causes muscle weakness. It is ordered when a doctor suspects MG based on symptoms like drooping eyelids, double vision, or difficulty chewing, swallowing, or speaking.
What it measures
- Acetylcholine receptor (AChR) antibodies — The most common antibody found in MG; a positive result supports the diagnosis.
- Muscle-specific kinase (MuSK) antibodies — Found in some people with MG who do not have AChR antibodies.
- LRP4 antibodies — A less common antibody that can be present in MG.
- Agrin antibodies — Another rare antibody that may be tested in some cases.
Who it is for
A neurologist or primary care doctor typically orders this test when a patient has symptoms suggesting MG or when other tests point to a neuromuscular junction disorder.
Preparation
No fasting or special preparation is usually required. Tell your doctor about any medications you take, as some can affect the test.
Results and what they mean
Results are reported as positive or negative for each antibody, sometimes with a numerical level. A positive result does not confirm MG by itself, and a negative result does not rule it out; a clinician interprets the results along with your symptoms and other tests. This is general information, not medical advice.
How to order this test
- Choose the test and place a confidential order online.
- Select a certified collection site and pick a time that suits you.
- Have your specimen collected — most draws take only a few minutes.
- Review results in a secure portal, typically within 1–3 days.
Preparation, hours, and pricing vary by site; confirm details directly with the lab before your visit.
Availability by state
Direct-access online ordering for the myasthenia gravis (mg) lab test is available in most states. It is currently unavailable in 6 states:
Everywhere else you can order confidentially and collect your sample at a certified site. Browse by state →
Frequently asked questions
Do I need to fast for this test?
No, fasting is not required. You can eat and drink normally before the blood draw.
How long does it take to get results?
Results are usually available within 1 to 3 business days.
What if my test is negative?
A negative result does not rule out MG. Some people with MG do not have these antibodies, so your doctor may order other tests.
Is this test covered by insurance?
Many insurance plans cover the test when ordered by a doctor. Check with your insurance provider for details.