An LC-MS/MS method for serum methylmalonic acid suitable for monitoring vitamin B12 status in population surveys1

Details

• Alternative Title:
  Anal Bioanal Chem
• Personal Author:
  Mineva, Ekaterina M. ; Zhang, Mindy ; Rabinowitz, Daniel J. ; Phinney, Karen W. ; Pfeiffer, Christine M.
• Description:
  Methylmalonic acid (MMA), a functional indicator of vitamin B12 insufficiency, was measured in the US population in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2004 using a GC/MS procedure that required 275 μL of sample and had a low throughput (36 samples/run). Our objective was to introduce a more efficient yet highly accurate LC-MS/MS method for NHANES 2011-2014. We adapted the sample preparation with some modifications from a published isotope-dilution LC-MS/MS procedure. The procedure utilized liquid-liquid extraction and generation of MMA dibutyl ester. Reversed-phase chromatography with isocratic elution allowed baseline resolution of MMA from its naturally occurring structural isomer succinic acid within 4.5 min. Our new method afforded an increased throughput (≤160 samples/run) and measured serum MMA with high sensitivity (LOD = 22.1 nmol/L) in only 75 μL of sample. Mean (±SD) recovery of MMA spiked into serum (2 d, 4 levels, 2 replicates each) was 94 % ± 5.5 %. Total imprecision (41 d, 2 replicates each) for three serum quality control pools was 4.9 %-7.9 % (97.1-548 nmol/L). The LC-MS/MS method showed excellent correlation (n = 326, r = 0.99) and no bias (Deming regression, Bland-Altman analysis) compared to the previous GC/MS method. Both methods produced virtually identical mean (±SD) MMA concentrations LC-MS/MS: 18.47 ± 0.71 ng/mL (n = 17), GC/MS: 18.18 ± 0.67 ng/mL (n = 11) on a future plasma reference material compared with a GC/MS method procedure from the National Institute of Standards and Technology 18.41 ± 0.70 ng/mL (n = 15). No adjustment will be necessary to compare previous (1999-2004) to future (2011-2014) NHANES MMA data.
• Keywords:
  • MMA
  • method comparison
  • GC/MS
  • anticoagulant types
  • NHANES
  • NIST SRM 1950
  • vitamin B12
  • Anticoagulants
  • Calibration
  • Chromatography, Liquid
  More +
• Source:
  Anal Bioanal Chem. 407(11):2955-2964
• Pubmed ID:
  25258283
• Pubmed Central ID:
  PMC4515767
• Document Type:
  Journal Article
• Funding:
  CC999999/Intramural CDC HHSUnited States/
• Volume:
  407
• Issue:
  11
• Download URL:
  https://stacks.cdc.gov/view/cdc/32443/cdc_32443_DS1.pdf
• File Type:
  [PDF - 1.17 MB]
• Collection(s):
  CDC Public Access
• Main Document Checksum:
  urn:sha256:e38a359383c139121310207989d5282b4d579f7fe6cd831ec42c0e8d155d4365