title: Methylmalonic acid and neutrophil morphometric index in laboratory diagnosis of cobalamin deficiency without macrocytosis.
abstract: BACKGROUND
  This study aimed to investigate the utility of methylmalonic acid (MMA) and neutrophil Cell Population Data, available on the Beckman Coulter LH750 Analyser (Miami, FL, USA), in laboratory assessment of cobalamin status in patients at risk of cobalamin deficiency, without macrocytosis and inflammation.
  
  
  METHODS
  The study group included 189 patients. Neutrophil Cell Population Data along with vitamin B12 and homocysteine were assessed in regard to MMA tertile groups.
  
  
  RESULTS
  Statistically significant differences were between lower and upper MMA tertile in serum B12 (P ˂ 0.001), homocysteine (P = 0.001) and neutrophil morphometric index, NeS-DW (P = 0.029). Also, serum B12 concentrations were significantly different between lower and middle MMA tertile, P = 0.005. Receiver operating characteristic analysis of NeS-DW ability to detect MMA˃367 nmol/L revealed a significant area under the curve AUC = 0.761 P ˂ 0.001 95% CI 0.693-0.830. Optimal cut-off value was NeS-DW˃3.51% with sensitivity of 74.19% and specificity of 68.87%.
  
  
  CONCLUSIONS
  In patients at risk of cobalamin deficiency and normal MCV, classification according to MMA revealed cobalamin status differences. Neutrophil morphometric index may be an indicator of early changes in neutrophil nucleus morphology caused by impaired cobalamin status.
authors.affiliation: Faculty of Pharmacy, Department of Medical Biochemistry, University of Belgrade, Belgrade, Serbia.
authors.forename: D
authors.initials: D
authors.lastname: Totoskovic
authors.affiliation: Faculty of Pharmacy, Department of Medical Biochemistry, University of Belgrade, Belgrade, Serbia.|Clinical Centre of Serbia, Center of Medical Biochemistry, Belgrade, Serbia.
authors.forename: V
authors.initials: V
authors.lastname: Dopsaj
authors.affiliation: Health Center Rakovica, Laboratory Department, Belgrade, Serbia.
authors.forename: J
authors.initials: J
authors.lastname: Martinovic
mesh_terms: D000368:Aged; D002467:Cell Nucleus / Q000378:metabolism / Q000473:pathology; D006710:Homocysteine / Q000097:blood; D006801:Humans; D008764:Methylmalonic Acid / Q000737:chemistry*; D008875:Middle Aged; D009504:Neutrophils / Q000378:metabolism / Q000473:pathology; D014806:Vitamin B 12 Deficiency / Q000097:blood / Q000175:diagnosis / Q000473:pathology
chemical_list: D006710:Homocysteine; D008764:Methylmalonic Acid
keywords: Cobalamin deficiency; LH750; methylmalonic acid; neutrophil morphometric index NeS-DW