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HelpTest Code MMAU Methylmalonic Acid, Quantitative, Urine
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Reporting Name
Methylmalonic Acid, QN, USpecimen Type
UrineSpecimen Required
Patient Preparation:
Fasting: 8 hours, required
Supplies: Urine Tubes, 10 mL (T068)
Container/Tube: Plastic, 10-mL urine tube
Specimen Volume: 4 mL
Collection Instructions:
1. After fasting at least 8 hours overnight, patient should void first-morning urine as normal. Do not collect.
2. Patient should continue to fast and then collect the next (second morning) urine voided.
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Urine | Frozen (preferred) | 28 days |
| Refrigerated | 28 days | |
| Ambient | 21 days |
Specimen Minimum Volume
1.2 mL
Day(s) Performed
Monday through Friday
Specimen Retention Time
1 weekReport Available
3 to 5 daysReference Values
<3.60 mmol/mol creatinine
Useful For
Evaluating children with signs and symptoms of methylmalonic acidemia using urine specimens
Evaluating individuals with signs and symptoms associated with a variety of causes of vitamin B12 (cobalamin) deficiency
CPT Code Information
83921
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| MMAU | Methylmalonic Acid, QN, U | 25116-5 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 80290 | Methylmalonic Acid, QN, U | 25116-5 |
Method Description
Methylmalonic acid (MMA) is determined by liquid chromatography tandem mass spectrometry (LC-MS/MS) stable isotope dilution analysis. The specimen is mixed with an internal standard (methyl-d3-malonic acid). MMA and d3-MMA are isolated by solid phase extraction. LC-MS/MS is performed using mobile phases and a short column to separate MMA and d3-MMA from the bulk of the specimen matrix. The MS/MS is operated in the multiple reaction monitoring (MRM) negative mode to follow the precursor to product species transitions. Separation of MMA/d3-MMA from the more physiologically abundant succinic acid is accomplished by the careful selection of MRM transitions and optimization of the LC separation. The ratios of the extracted peak areas of MMA to d3-MMA determined by LC-MS/MS are used to calculate the concentration of MMA present in the sample.(Unpublished Mayo method)
Disease States
- Homocystinuria
Forms
If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
-Biochemical Genetics Test Request (T798)
-Benign Hematology Test Request (T755)