Due to the high volume of sample submissions, we feel that we can better serve you and answer your questions by email. Please send questions directly to the laboratory technicians at musclelab@ucsd.edu. The laboratory staff welcomes email consultation with referring veterinarians or associated lab staff but cannot answer questions directly to pet owners. Examples of the most frequently asked questions follow below.
1. What type of sample do we need to submit for a 2M antibody (masticatory muscle myositis) or acetylcholine receptor (AChR) antibody (myasthenia gravis) test? How long does it take to get results back?
Send 1-2 ml of serum (not whole blood) in a red top or serum separator tube by an overnight service. In the hot summer months it is good to include a cold pack, but in the cooler months the cold pack is not necessary. The turnaround time is 5-7 working days (does not include week-ends or holidays) from the day the sample arrives.
2. What is the cost of testing and does payment need to be submitted with the sample?
Downloadable sample submission forms with all costs and shipping requirements can be found here. If a FAX copy of submission forms is required, call the laboratory technicians at 858-534-1537. Payment may be included with the sample or billing can be requested. If a check is submitted, please make payable to UC Regents. If billing is requested, please include a business card on initial submission. International customers must submit a credit card number (Visa or MasterCard) either with the sample on submission or faxed to 858-534-0391.
3. Can medications have an effect on the results of antibody testing for masticatory muscle myositis (2M antibody) or myasthenia gravis (AChR antibody)?
Treatment with corticosteroids (prednisone, dexamethasone, and triamcinoline) at immunosuppressive doses (1mg/lb/day for longer than 7-10 days) can therapeutically lower antibody titers and result in a negative test for both myasthenia gravis and masticatory muscle myositis. It is ideal to collect the serum sample PRIOR to beginning corticosteroid therapy and store in the freezer for possible future testing. Anticholinesterase drugs such as Mestinon will not have an effect on antibody testing.
4. What if the sample is lipemic or hemolyzed?
For the antibody tests in general (2M and AChR antibody), lipemia and hemolysis do not affect the results of testing. However, if a sample is severely lipemic (looks like cream) or hemolyzed (looks like port wine), please draw another sample.
5. Does the patient have to be fasted before drawing a blood sample?
It is always best to have a non-lipemic blood sample, so an overnight fast is suggested.
6. If the serum sample is less than 1-2 ml can testing still be performed?
The 2M and AChR antibody tests can be performed with as little as 500 uL of serum. However, package the sample well to prevent any leakage during shipping.
7. If it is necessary to draw a serum sample on Friday (laboratory is closed week-ends) or cannot be shipped the same or next day, how should the sample be stored?
Serum samples can be stored for a week refrigerated. For longer storage, the sample should be frozen. When a previously frozen sample for 2M or AChR antibody testing is shipped, it does not have to remain frozen. In the summer months a cold pack should be included.
8. Is it possible to run a 2M or AChR antibody test STAT?
We do not offer a STAT service for either test. 2M antibody testing is performed in batches and run 2-3 times per week depending on workload. The AChR antibody testing for myasthenia gravis, however, is run daily during workdays, as MG can be a fatal disease.
9. What is your Test Cancellation Policy?
Cancellation of a test request must be must be made within 24 hours of receipt of sample and before specimen testing has started. We regret that a cancellation request received after testing has started or after the test result has been reported cannot be honored.
Adding a Test on the Same Speciman:
Provided that an adequate quantity of a specimen is available, additional tests may be requested on a specimen within one month of specimen receipt. Each additional request will be billed to the appropriate party. Any additions to samples submitted via Antech, Idexx, or other reference laboratory must be made by the submitting laboratory.
Cancelling or Revising a Test Request:
Please complete the Test Cancellation Request Form (.pdf) and submit to the laboratory via email (musclelab@ucsd.edu) or fax (858-534-0391). If you have any questions, please contact the Comparative Neuromuscular Laboratory at 858-534-1537. After 24 hours, requests for cancellation will be handled on a case-by-case basis.
10. How long are serum samples stored in the laboratory?
Serum samples are stored for 6 weeks then discarded.
11. Can test results be sent to a different fax number or clinic than what is indicated on the sample submission form?
Results of testing are sent by fax to the clinic and fax number included on the sample submission form. Verbal test results may be given over the phone to the veterinarian or the veterinary technician from the clinic submitting the testing. If results need to be sent to another clinic, it is up to the veterinarian to do this.
12. How accurate is the Acetylcholine Receptor Antibody (MG) test?
The test for myasthenia gravis performed in our laboratory (acetylcholine receptor antibody titer determined by radioimmunoassay) is 98% accurate for generalized acquired myasthenia gravis. 2% of the cases will be seronegative. If the onset of clinical signs is recent and the antibody test negative, retesting in 3 weeks is suggested. The AChR antibody test does not diagnose cases of congenital MG. If congenital myasthenia is suspected, the veterinarian should contact Dr. Shelton for consultation. For commonly asked question about Myasthenia Gravis (MG) and other cases pertaining to MG, please refer to our Myasthenia Gravis page.
13. How sensitive is the 2M antibody test?
The 2M antibody test is an ELISA based test and is very sensitive and specific. A negative antibody titer may occur in end-stage masticatory muscle myositis (muscle biopsy needed), in polymyositis (muscle biopsy needed) or if the dog has been on immunosuppressive dosages of corticosteroids for longer than 7-10 days. For commonly asked questions about Masticatory Muscle Myositis(MMM) and other cases pertaining to MMM, please refer to our Myositis page.
14. How should muscle samples be shipped?
Two muscle biopsies should be collected from each site. Wrap the largest biopsy specimen (0.5 X 0.5 X 1.0 cm) in a saline dampened (NOT DRIPPING WET) gauze sponge and placed into a dry water-tight container (for example, a 10 ml red top tube) and keep cold until shipped. A second smaller biopsy specimen from next to the original biopsy should be placed directly into 10% buffered formalin. Place all muscle specimens into a Styrofoam box with cold packs and ship by an overnight night service so the samples arrive into the laboratory within 24-36 hours of collection. It is critical that the muscle biopsies remain cold so we receive the tissue in good condition. A special collection technique is required for biopsy of a masticatory muscle. For collection of temporalis muscle biopsies, refer to our How to take a Muscle Biopy page.
15. What does a complete muscle profile include?
Please refer to our Complete Muscle Profile page.
16. If a muscle/nerve biopsy is done on a Friday or cannot be shipped right away, how should the muscle sample be stored?
Please make every effort possible NOT to collect muscle on a Friday. Expedited service to the laboratory by an overnight service on cold packs provides the best sample quality. IF IT IS ABSOLUTELY NECESSARY TO COLLECT BIOPSIES ON A FRIDAY, place the muscle in the refrigerator over the weekend and ship out on Monday on cold packs by an overnight service. NEVER FREEZE FORMALIN FIXED MUSCLE OR NERVE TISSUE. Hold those biopsies at room temperature.
17. Will corticosteroids or other medications affect the results of a muscle biopsy?
Chronic corticosteroid therapy will result in type 2 muscle fiber atrophy, which can be determined in the biopsy sections by fiber typing. Other pathological changes should not be affected.
18. What information is needed to set up an account for a new customer?
Once a sample is received with a completed sample submission form, an account is created and a new customer number assigned. Accounts are not created prior to receiving samples.