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Lab Dept:
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Urine/Stool
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Test Name:
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METHYLMALONIC ACID (MMA), URINE
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General Information
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Lab Order Codes:
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MMAU
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Synonyms:
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MMA, Urine
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CPT Codes:
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83921 – Organic acid, single, quantitative
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Test Includes:
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Quantitative MMA level reported in umol/L.
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Logistics
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Test Indications:
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Evaluating children with signs and symptoms of methylmalonic Acidemia. Screening for the differential diagnosis of signs and symptoms associated with a variety of causes of cobalamin deficiency. Serum MMA may be a more reliable marker of cobalamin deficiency than direct cobalamin determination.
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Lab Testing Sections:
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Chemistry - Sendouts
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Referred to:
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Mayo Medical Laboratories (MML Test: MMAU/80290)
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Phone Numbers:
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MIN Lab: 612-813-6280
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STP Lab: 651-220-6550
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Test Availability:
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Daily, 24 hours
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Turnaround Time:
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3 - 5 days, performed Monday - Friday
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Special Instructions:
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Overnight fast recommended prior to specimen collection. See Collection.
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Specimen
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Specimen Type:
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Random urine
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Container:
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Urine container
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Draw Volume:
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4 mL (Minimum: 1.2 mL) second-voided urine
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Processed Volume:
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Same as Draw Volume
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Collection:
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Second-voided urine specimen after an overnight fast.
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Special Processing:
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Lab Staff: Send urine specimen aliquot frozen in a plastic, 13 mL urine tube. Forward promptly.
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Patient Preparation:
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Second-voided urine specimen after an overnight fast.
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Sample Rejection:
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Warm specimen; specimens other than urine
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Interpretive
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Reference Range:
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<3.60 mmol/mol creatinine
In pediatric patients, markedly elevated MMA values are consistent with a diagnosis of methylmalonic acidemia.
In adults, moderately elevated MMA values indicate a likely cobalamin deficiency.
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Critical Values:
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N/A
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Limitations:
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Diet, nutritional status, and age should be considered in the evaluation of serum MMA level.
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Methodology:
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Liquid chromatography-tandem mass spectrometry stable isotope dilution analysis (LC-MS/MS).
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References:
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Mayo Medical Laboratories May 2013
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