Metachromatic Leucodystrophy, Quantitative (ARSA) Test: Booking, Price, and Results
About Metachromatic Leucodystrophy, Quantitative (ARSA) Test: Booking, Price, and Results
| Field | Value |
|---|---|
| Also Known As | ARSA test, arylsulfatase A test, ASA test, MLD enzyme test |
| Sample Type | Whole blood (EDTA tube) |
| Fasting Required | No fasting required |
| Report Time | 6 days |
| Recommended For | All ages; infants, children, and adults with suspected Metachromatic Leucodystrophy (MLD) or a family history of the condition |
| Price | Starting at ₹2,950 |
What Is an MLD (ARSA) Test?
The MLD (ARSA) test measures the activity of the arylsulfatase A enzyme in white blood cells. This enzyme is responsible for breaking down a type of fat called sulfatides. When the enzyme is deficient, sulfatides accumulate in the brain and nervous system, damaging the myelin sheath — the protective covering around nerve fibres.
Also known as the ARSA test or arylsulfatase A test, it is ordered for individuals with symptoms suggesting metachromatic leucodystrophy (MLD) or with a known family history of the condition. A small sample of whole blood is collected for this test.
What Does an MLD (ARSA) Test Measure?
The test analyses arylsulfatase A enzyme activity in leucocytes (white blood cells) isolated from your blood sample. Below is a summary of what is assessed.
| Parameter | What It Tells Us |
|---|---|
| ARSA Enzyme Activity (Leucocytes) | Whether the arylsulfatase A enzyme is present at sufficient levels to break down sulfatides normally |
Low enzyme activity suggests that sulfatides may be building up in the nervous system, pointing to a possible diagnosis of MLD or a related condition. The test uses a method called spectrophotometry to measure enzyme activity precisely.
Why Is an MLD (ARSA) Test Done?
This is a specialised test ordered when a doctor suspects a rare inherited disorder affecting the nervous system. It is primarily used to support the diagnosis of metachromatic leucodystrophy (MLD). It may also be used during the evaluation of at-risk family members, although genetic testing is usually required for definitive assessment.
Common Symptoms That May Require This Test
A doctor may order this test when a patient shows one or more of the following signs:
- Muscle weakness or low muscle tone (hypotonia) in infants or young children
- Frequent falls, clumsiness, or difficulty walking
- Toe walking or changes in the way a child walks
- Difficulty speaking (dysarthria) or regression in language skills
- Loss of previously acquired motor or cognitive abilities
- Muscle stiffness or abnormal involuntary movements (spasticity)
- Seizures or unexplained vision problems
Conditions This Test Can Help Detect
The following conditions may be identified through this test:
- Metachromatic leucodystrophy (MLD): a rare inherited disorder caused by deficient ARSA enzyme activity, leading to progressive damage of the nervous system.
- Multiple sulfatase deficiency: a condition in which arylsulfatase A and other sulfatase enzymes are all deficient.
- ARSA pseudodeficiency: a genetic variant associated with low ARSA enzyme activity despite the absence of MLD.
- Evaluation of at-risk family members of an individual diagnosed with MLD, often alongside genetic testing.
- Follow-up evaluation after an abnormal newborn screening result in regions where MLD newborn screening is offered.
How to Prepare and What to Expect
No special preparation is needed before the MLD (ARSA) test. The process is straightforward and similar to a routine blood draw.
Do You Need to Fast?
No, fasting is not required for this test. You may eat and drink normally before sample collection.
Practical Tips Before Your Test
A few simple steps will help ensure the sample is collected and handled correctly:
- Provide details of symptoms, previous investigations, and relevant family history whenever possible, as this information helps with interpretation of the results.
- Inform your doctor about any recent blood transfusions or major medical procedures, as these may affect interpretation of the results.
- Let the laboratory know if there is a known family history of MLD or any related genetic condition.
- Wear loose, comfortable clothing that allows easy access to your arm.
Step-by-Step Procedure
Here is what to expect during sample collection:
- A trained phlebotomist will clean a small area on your arm with an antiseptic solution.
- A needle is inserted briefly to collect approximately 2 mL of whole blood into an EDTA (lavender-top) tube.
- The tube is labelled and stored refrigerated at 2°C to 8°C; it is not frozen, as freezing can damage the sample.
- The sample is transported promptly to the laboratory to preserve enzyme activity and allow proper leucocyte isolation.
- In the laboratory, white blood cells are separated from the blood, and ARSA enzyme activity is measured using a validated laboratory enzyme assay.
- Results are prepared and delivered within 6 days of sample receipt.
Factors That Can Affect Accuracy
The following factors may influence the reliability of your results:
- ARSA pseudodeficiency, which can result in low enzyme activity despite the absence of MLD.
- Improper specimen handling or storage during transport.
- Delayed arrival of the sample at the laboratory.
- Overlap in enzyme activity levels between affected individuals, carriers, and those with ARSA pseudodeficiency.
- Recent blood transfusions before sample collection.
Understanding Your MLD (ARSA) Test Results
Results from this test must be reviewed by a specialist doctor alongside your symptoms, MRI findings, and clinical history. The table below shows how ARSA enzyme activity results are generally interpreted.
| ARSA Activity (Leucocytes) Result | Interpretation |
|---|---|
| ≥ 62 nmol/h/mg protein | Generally indicates normal ARSA enzyme activity; MLD is less likely. Results should still be interpreted in the context of clinical findings and, where appropriate, genetic testing. |
| < 62 nmol/h/mg protein | Reduced ARSA enzyme activity detected. This may occur in MLD, ARSA pseudodeficiency, multiple sulfatase deficiency, or other rare situations. Additional investigations (such as urine sulphatide analysis and/or ARSA genetic testing) are usually needed to determine the cause. |
| Markedly low activity (for example, <10% of the laboratory’s lower reference limit) | Strongly raises suspicion for MLD, but does not by itself confirm the diagnosis. Correlation with clinical findings, MRI, and confirmatory biochemical and/or genetic testing is required. |
Disclaimer: These interpretations are general guidelines. Your doctor will interpret your results based on your age, health history, MRI findings, and other laboratory tests. Always consult a qualified healthcare professional for personalised medical advice.
Results During Special Conditions
Pseudodeficiency of ARSA is an important consideration when interpreting results. Some individuals, including those with other unrelated neurological conditions, may have very low enzyme activity but do not have MLD. Pseudodeficiency is difficult to distinguish from true enzyme deficiency using biochemical testing alone, and additional molecular or urine testing may be needed to clarify the diagnosis.
How to Maintain Healthy Levels
Because MLD is an inherited genetic condition, enzyme activity cannot be changed through diet or lifestyle. The following general points apply:
- Genetic counselling is recommended for families with a confirmed diagnosis of MLD to understand the risk to other family members.
- Early specialist referral can help explore available clinical options.
- Regular follow-up with a neurologist is advisable for individuals with confirmed low ARSA activity.
Lupin Diagnostics Metachromatic Leucodystrophy, Quantitative (ARSA) Test Price and Home Collection
The MLD (ARSA) test is available at Lupin Diagnostics starting at ₹2,950, with home sample collection offered across multiple cities. The table below shows indicative pricing by city.
| City | Approximate Price (₹) |
|---|---|
| BHOPAL | 2950 |
| HYDERABAD | 2950 |
| KOLKATA | 2950 |
| NAVI MUMBAI | 2950 |
| PUNE | 2950 |
Disclaimer: Prices are indicative and may vary by location. Please confirm the current price at the time of booking.
How to Book
Booking your MLD (ARSA) test at Lupin Diagnostics is straightforward:
- Select the test on the Lupin Diagnostics website.
- Choose your city and preferred time slot.
- If available for your location and test type, 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 blood collection for the MLD (ARSA) test across cities, making it convenient for patients who find travel difficult. All samples are processed in NABL-accredited laboratories by qualified professionals. Digital reports are accessible via email or WhatsApp once ready.
Frequently Asked Questions
The MLD (ARSA) test measures arylsulfatase A enzyme activity in white blood cells. It helps doctors investigate whether a deficiency of this enzyme is causing progressive damage to the nervous system, which is characteristic of metachromatic leucodystrophy. It is used both for initial diagnosis and for screening at-risk family members.
Metachromatic leucodystrophy is a rare inherited condition in which a shortage of the ARSA enzyme causes a fatty substance called sulfatides to build up in the nervous system. This leads to progressive damage to the myelin sheath around nerves. MLD can present in infancy, childhood, or adulthood, depending on the form.
A low result may indicate MLD, multiple sulfatase deficiency, or ARSA pseudodeficiency. In pseudodeficiency, enzyme levels appear low, but the person has no symptoms of MLD. Because these situations can look similar on this test, a low result is typically followed by additional testing, such as urine sulfatide analysis or molecular genetic testing, before a final diagnosis is made.
No, the MLD (ARSA) test is not reliable for identifying carriers. Individual variation in enzyme levels means that some carriers may have results in the normal range, while some unaffected individuals may have results that appear low. Molecular genetic testing is more appropriate for carrier detection.
The report is typically available within 6 days of sample collection at Lupin Diagnostics. This test requires leucocyte isolation and specialised enzyme measurement, which takes longer than routine blood tests.
Yes, an abnormal result alone is not sufficient to confirm a diagnosis of MLD. Your doctor may request urine sulphatide testing and ARSA genetic testing to confirm the diagnosis and distinguish true MLD from ARSA pseudodeficiency. These additional tests help clarify the cause of reduced enzyme activity.
Yes, in regions where MLD newborn screening is available, ARSA testing may be used as a follow-up test after an abnormal newborn screening result suggesting possible MLD. It is suitable for all ages, from newborns through to adults, whenever there is a clinical reason to test for arylsulfatase A deficiency.
Metachromatic Leucodystrophy, Quantitative (ARSA) Test: Booking, Price, and Results
