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Isotope-dilution assay for urinary methylmalonic acid in the diagnosis of vitamin B12 deficiency. A prospective clinical evaluation.

Publication ,  Journal Article
Matchar, DB; Feussner, JR; Millington, DS; Wilkinson, RH; Watson, DJ; Gale, D
Published in: Ann Intern Med
May 1987

Vitamin B12 deficiency is a frequently considered diagnosis for which there is no single, commonly available and accurate test. A urinary methylmalonic acid assay using gas chromatography-mass spectrometry has been proposed as the preferred test. We reviewed vitamin B12 assays on 1599 consecutive patients and prospectively studied all patients with low serum B12 levels (n = 75) and a random sample of patients with normal levels (n = 68). Of 96 evaluable patients, 7 had clinical deficiency. All 7 deficient patients had urinary methylmalonic acid levels greater than 5 micrograms/mg creatine (sensitivity, 100%; confidence interval, 65% to 100%). Of the 89 patients who were not clinically deficient, 88 had urinary methylmalonic acid levels less than or equal to 5 micrograms/mg creatinine (specificity, 99%). The overall test accuracy in this population was 99%. If the high sensitivity and specificity of the gas chromatography-mass spectrometry assay for urinary methylmalonic acid is supported by other clinical studies, the methylmalonic acid assay may become the reference standard for the diagnosis of vitamin B12 deficiency.

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Published In

Ann Intern Med

DOI

ISSN

0003-4819

Publication Date

May 1987

Volume

106

Issue

5

Start / End Page

707 / 710

Location

United States

Related Subject Headings

  • Vitamin B 12 Deficiency
  • Vitamin B 12
  • Prospective Studies
  • Predictive Value of Tests
  • Middle Aged
  • Methylmalonic Acid
  • Malonates
  • Male
  • Indicator Dilution Techniques
  • Humans
 

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Matchar, D. B., Feussner, J. R., Millington, D. S., Wilkinson, R. H., Watson, D. J., & Gale, D. (1987). Isotope-dilution assay for urinary methylmalonic acid in the diagnosis of vitamin B12 deficiency. A prospective clinical evaluation. Ann Intern Med, 106(5), 707–710. https://doi.org/10.7326/0003-4819-106-5-707
Matchar, D. B., J. R. Feussner, D. S. Millington, R. H. Wilkinson, D. J. Watson, and D. Gale. “Isotope-dilution assay for urinary methylmalonic acid in the diagnosis of vitamin B12 deficiency. A prospective clinical evaluation.Ann Intern Med 106, no. 5 (May 1987): 707–10. https://doi.org/10.7326/0003-4819-106-5-707.
Matchar DB, Feussner JR, Millington DS, Wilkinson RH, Watson DJ, Gale D. Isotope-dilution assay for urinary methylmalonic acid in the diagnosis of vitamin B12 deficiency. A prospective clinical evaluation. Ann Intern Med. 1987 May;106(5):707–10.
Matchar, D. B., et al. “Isotope-dilution assay for urinary methylmalonic acid in the diagnosis of vitamin B12 deficiency. A prospective clinical evaluation.Ann Intern Med, vol. 106, no. 5, May 1987, pp. 707–10. Pubmed, doi:10.7326/0003-4819-106-5-707.
Matchar DB, Feussner JR, Millington DS, Wilkinson RH, Watson DJ, Gale D. Isotope-dilution assay for urinary methylmalonic acid in the diagnosis of vitamin B12 deficiency. A prospective clinical evaluation. Ann Intern Med. 1987 May;106(5):707–710.

Published In

Ann Intern Med

DOI

ISSN

0003-4819

Publication Date

May 1987

Volume

106

Issue

5

Start / End Page

707 / 710

Location

United States

Related Subject Headings

  • Vitamin B 12 Deficiency
  • Vitamin B 12
  • Prospective Studies
  • Predictive Value of Tests
  • Middle Aged
  • Methylmalonic Acid
  • Malonates
  • Male
  • Indicator Dilution Techniques
  • Humans