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methylmalonate in serum

Metabolism of methylmalonate is dependent upon vitamin B12, cofactor for methylmalonyl-CoA-mutase. Normal range: 1) < 4.72 ug/dL (0.40-0.56 umol/L) [3] 2) 53-376 nmol/L [4] 3) 0.08-0.28 umol/L [6] 4) variation within an individual over time is 34% [6] 5) not strongly correlated with serum B12 (r = -0.22) [6] Clinical significance: - reflect cobalamin tissue stores - elevated levels confirm vitamin B12 deficiency in patients with low normal serum vitamin B12 levels [1] - elevated levels do not predict a further increase with time & clinical manifestations of vitamin B12 deficiency [6] Increases: 1) vitamin B12 deficiency (but NOT folate deficiency) 2) congenital methylmalonic aciduria 3) renal insufficiency* (even mild renal insufficiency) 4) hypovolemia 5) overgrowth of intestinal propionic acid-producing bacteria * For 3-fold increase in serum creatinine, roughly a 2-fold increase in methylmalonate in serum may be expected [3] Methods: - GC-MS Specimen: - serum, fasting - analyze fresh or store at -70 degrees C [3] - stable indefinitely at -20 C [4]

Related

methylmalonate in urine methylmalonate; methylmalonic acid (MMA)

General

methylmalonate in body fluid

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 11, 19. American College of Physicians, Philadelphia 1998, 2022
  2. Clinical Guide to Laboratory Tests, 3rd edition, NW Tietz ed, WB Saunders, Philadelphia, 1995
  3. Tietz Textbook of Clinical Chemistry, 2nd ed. Burtis CA & Ashwood ER (eds), WB Saunders Co, Philadelphia PA, 1993, pg 2057
  4. Savage DG et al Sensitivity of serum methylmalonic acid and total homocysteine determinations for diagnosing cobalamin and folate deficiencies. Am J Med 96:239, 1994
  5. Smith R. Jewish Home for the Aging, Reseda CA, 2001, unpublished manuscript
  6. Hvas AM et al, Increased plasma methylmalonic acid level does not predict clinical manifestations of vitamin B12 deficiency. Arch Intern Med 161:1534, 2001 PMID: 11427102
  7. MMA Serum/Plasma, Vitamin B12 Deficiency Laboratory Test Directory ARUP: 99431
  8. MMA Serum/Plasma, Metabolic Disorder Laboratory Test Directory ARUP: 2005255
  9. Mini Panel of 2 tests: MEN Type 1 (MEN1) Del/Dup Interpretation . MEN Type 1 (MEN1) Del/Dup Specimen Laboratory Test Directory ARUP: 2005346

Component-of

methylmalonate/homocysteine in serum/plasma