methylmalonate in serum
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Introduction
Metabolism of methylmalonate is dependent upon vitamin B12, cofactor for methylmalonyl-CoA-mutase.
Reference interval
- < 4.72 ug/dL (0.40-0.56 umol/L)[3]
- 53-376 nmol/L[4]
- 0.08-0.28 umol/L[6]
- variation within an individual over time is 34%[6]
- 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
- vitamin B12 deficiency (but NOT folate deficiency)
- congenital methylmalonic aciduria
- renal insufficiency* (even mild renal insufficiency)
- hypovolemia
- 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
Specimen
More general terms
Additional terms
Component of
References
- ↑ 1.0 1.1 Medical Knowledge Self Assessment Program (MKSAP) 11, 19. American College of Physicians, Philadelphia 1998, 2022
- ↑ Clinical Guide to Laboratory Tests, 3rd edition, NW Tietz ed, WB Saunders, Philadelphia, 1995
- ↑ 3.0 3.1 3.2 3.3 Tietz Textbook of Clinical Chemistry, 2nd ed. Burtis CA & Ashwood ER (eds), WB Saunders Co, Philadelphia PA, 1993, pg 2057
- ↑ 4.0 4.1 4.2 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
- ↑ Smith R. Jewish Home for the Aging, Reseda CA, 2001, unpublished manuscript
- ↑ 6.0 6.1 6.2 6.3 6.4 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: https://www.ncbi.nlm.nih.gov/pubmed/11427102
- ↑ MMA Serum/Plasma, Vitamin B12 Deficiency Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0099431.jsp
- ↑ MMA Serum/Plasma, Metabolic Disorder Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0000000.jsp
- ↑ Mini Panel of 2 tests: MEN Type 1 (MEN1) Del/Dup Interpretation . MEN Type 1 (MEN1) Del/Dup Specimen Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0000000.jsp