NMDA Receptor Antibody Serum Test
About NMDA Receptor Antibody Serum Test
| Field | Value |
|---|---|
| Also Known As | Anti-NMDA Receptor Antibody Test, Anti-NMDAR Antibody Serum, NR1 Antibody Serum Test, Anti-Glutamate Receptor Antibody Test, NMDAR IgG Antibody |
| Sample Type | Venous blood (serum) |
| Fasting Required | No fasting required |
| Report Time | 5 to 10 days (specialised test requiring referral lab processing) |
| Recommended For | All ages and genders; most commonly ordered for young women with suspected autoimmune encephalitis |
| Price | Starting at ₹5,000 |
What Is a NMDA Receptor Antibody Serum Test?
The NMDA Receptor Antibody Serum test detects specific antibodies in the blood that target proteins in the brain called NMDA receptors. These receptors play a key role in how nerve cells communicate, and when the immune system mistakenly attacks them, it can cause serious neurological symptoms. Also known as the Anti-NMDA receptor antibody serum test or the NR1 antibody serum test, this test is typically ordered by neurologists or psychiatrists when autoimmune brain inflammation is suspected. A blood sample is drawn from a vein in the arm and processed in a specialised laboratory.
What Does a NMDA Receptor Antibody Serum Test Measure?
This test looks for IgG antibodies (a type of immune protein) that attack the NR1 subunit of the NMDA receptor in the brain and nervous system. Here is what each element of the test involves:
| Component | What It Means |
|---|---|
| NMDA Receptor | A protein found on nerve cells that controls electrical signals and plays a key role in memory and learning |
| NR1 Subunit | The specific part of the NMDA receptor that the antibodies target in this condition |
| IgG Antibodies (IgG1 and IgG3) | Immune proteins that attach to the NR1 subunit, causing the receptor to be drawn into the cell and reducing its function |
| Antibody Status (Positive or Negative) | Whether these antibodies are present or absent in the blood sample |
Why Is a NMDA Receptor Antibody Serum Test Done?
This test is ordered when a doctor suspects that the brain is being affected by the body's own immune system. The following sections explain the common reasons for ordering it.
Common Symptoms That May Require This Test
A doctor may recommend the NMDAR antibody blood test when a patient presents with one or more of the following symptoms:
- Hallucinations (hearing or seeing things that are not there)
- Sudden changes in behaviour or personality, often with agitation
- Seizures (fits or convulsions)
- Reduced or fluctuating levels of consciousness
- Memory problems or confusion
- Abnormal movements such as repetitive jerking or stiffness
- Problems with automatic body functions, such as irregular heart rate or blood pressure
Conditions This Test Can Help Detect
The autoimmune encephalitis serum test can help identify several conditions. These include:
- Anti-NMDA receptor encephalitis, a treatable autoimmune disorder with prominent psychiatric and neurological features
- Autoimmune limbic encephalitis, which affects brain areas linked to memory and emotion, with or without an associated tumour
- Paraneoplastic syndrome, where antibody production is triggered by an underlying tumour, most often an ovarian teratoma
- Post-viral autoimmune encephalitis, particularly following herpes simplex virus (HSV) brain infection
NMDA Receptor Antibody Serum Test for Chronic Disease Monitoring
Once a patient is diagnosed with anti-NMDAR encephalitis, this test may be repeated over time to track how well treatment is working. Falling antibody levels in the blood can indicate a positive response to immunotherapy (treatments that modify the immune system's activity). Regular monitoring helps the treating neurologist adjust the treatment plan as needed.
How to Prepare and What to Expect
The test preparation is straightforward, and the procedure itself is brief. Here is what to keep in mind before your appointment.
Do You Need to Fast?
No, fasting is not required for this test. You can eat and drink as usual before your sample is collected. If other tests have been ordered alongside this one, check with your doctor, as those may have different preparation requirements.
Practical Tips Before Your Test
- Inform your doctor about all medications you are currently taking, as some may affect results
- Mention any history of tumours, psychiatric conditions, or neurological disorders to your doctor
- Drink plenty of water before the appointment to make veins easier to access
- Wear a short-sleeved or loose-fitting top for easy access to your arm
Step-by-Step Procedure
The blood collection process for the NMDA antibody test follows these steps:
- A trained phlebotomist (the person who draws blood) will clean the inside of your arm with an antiseptic solution
- A soft elastic band is placed around your upper arm to make your veins more visible
- A small needle is inserted into a vein and blood is drawn into a specialised serum separator tube
- The sample must be processed quickly; serum is separated from blood cells within two hours of collection
- The sample is centrifuged (spun at high speed to separate its components) and transferred into a secure vial
- The serum is refrigerated and dispatched to a referral laboratory for analysis
Factors That Can Affect Accuracy
Certain conditions can affect the quality of results. These include:
- Samples that are contaminated, haemolysed (containing broken red blood cells), or heavily fatty (lipaemic)
- Delays in separating serum from blood cells after collection
- Repeated freezing and thawing of the sample before analysis
- Testing serum alone without a matching cerebrospinal fluid (CSF) sample, which can reduce diagnostic sensitivity
Understanding Your NMDA Receptor Antibody Serum Test Results
Your results should always be reviewed with a qualified doctor who can consider them alongside your symptoms, medical history, and other tests. The table below explains the possible outcomes.
| Result | Reference Range | Interpretation |
|---|---|---|
| NMDA Receptor Antibody (IgG) | Negative (Not Detected) | No antibodies against NMDA receptors found; autoimmune NMDAR encephalitis is less likely |
| NMDA Receptor Antibody (IgG) | Positive (Detected) | Antibodies present; suggests possible anti-NMDA receptor encephalitis or related autoimmune condition |
| Low Positive | Borderline Detected | May still be clinically significant; requires correlation with symptoms and additional testing |
These ranges are general guidelines. Your doctor will interpret your results based on your age, health history, and other factors. Always consult a qualified healthcare professional for personalised medical advice.
Results During Special Conditions
Certain situations can influence how results are interpreted. Your doctor will take these into account:
- Viral infection history: HSV encephalitis can trigger the production of NMDA receptor antibodies. Early return of symptoms within two to three weeks of an HSV brain infection may indicate that anti-NMDAR encephalitis has been triggered by the virus, rather than a recurrence of the original infection.
- Tumour-related findings: Patients with an associated tumour, especially ovarian teratoma, often show higher levels of these antibodies in the blood. A positive result may prompt further investigation to look for an underlying tumour.
- Treatment monitoring: Antibody levels that fall over time are generally linked to a positive response to treatment. A persistently positive result may prompt a review of the current treatment approach.
How to Maintain Healthy Levels
These general wellness habits support overall immune and neurological health:
- Follow a balanced diet with adequate vitamins and minerals to support immune function
- Prioritise regular sleep, as it plays a key role in brain health and immune regulation
- Keep all follow-up appointments with your neurologist if you have received a positive result
Lupin Diagnostics NMDA Receptor Antibody Serum Test Price and Home Collection
The NMDA receptor antibody serum test price varies by city. Lupin Diagnostics offers home sample collection for this test across major Indian cities. The table below provides approximate prices based on current aggregator data:
| City | Approximate Price (₹) |
|---|---|
| Mumbai | ₹9,000 |
| Bangalore | ₹9,000 |
| Hyderabad | ₹9,000 |
| Chennai | ₹9,000 |
| Kolkata | ₹9,000 |
Prices are indicative and may vary by location. Please confirm the current price at the time of booking.
How to Book
- Select the test on the Lupin Diagnostics website.
- Choose your city and preferred time slot.
- Opt for home sample collection by a certified phlebotomist, or visit your nearest Lupin Diagnostics centre.
- Receive your report via email or WhatsApp within the stipulated turnaround time.
Home Collection
Lupin Diagnostics offers home collection for the NMDA receptor antibody test near me across major cities in India, so you do not need to visit a centre for sample collection. All samples are processed in NABL-accredited laboratories by trained professionals. Your digital report is delivered securely via email or WhatsApp once ready.
Frequently Asked Questions
The NMDA Receptor Antibody Serum test is primarily used to confirm a diagnosis of anti-NMDAR encephalitis, a type of autoimmune brain inflammation. It may also be used to monitor how well treatment is working in patients who have already tested positive for these antibodies.
No fasting is needed before the NMDA antibody test. You can eat and drink normally on the day of your appointment. If other tests have been ordered at the same time, check with your doctor in case those require fasting.
This test is typically recommended for people who have unexplained seizures, sudden behavioural changes, hallucinations, memory loss, or abnormal movements. It may also be suggested for those with a history of autoimmune disorders or a recently diagnosed tumour, particularly an ovarian teratoma.
A positive result suggests the presence of antibodies against NMDA receptors, which points towards autoimmune encephalitis or a related condition. It does not confirm the diagnosis on its own. Your doctor will order further tests, including CSF analysis and brain imaging, to build a complete picture.
The test itself does not detect tumours directly. However, a positive result can prompt doctors to investigate for an associated tumour. Ovarian teratomas are found in a notable proportion of affected patients, most often in women between the ages of 12 and 45.
Report time is typically 5 to 10 days, as this is a specialised test that requires processing at a referral laboratory. Turnaround times may vary depending on the laboratory and the volume of testing at the time.
Serum testing for the autoimmune encephalitis serum test can detect NMDAR IgG antibodies in over 80% of affected patients. However, CSF (cerebrospinal fluid) testing is considered more sensitive. Doctors often recommend testing both samples together to improve diagnostic accuracy, particularly when clinical suspicion is high.
NMDA Receptor Antibody Serum Test: Booking, Price, and Results
