title: Comparison of haemoglobin estimates using direct & indirect cyanmethaemoglobin methods.
abstract: OBJECTIVE
  Estimation of haemoglobin is the most widely used method to assess anaemia. Although direct cyanmethaemoglobin method is the recommended method for estimation of haemoglobin, but it may not be feasible under field conditions. Hence, the present study was undertaken to compare indirect cyanmethaemoglobin method against the conventional direct method for haemoglobin estimation.
  
  
  METHODS
  Haemoglobin levels were estimated for 888 adolescent girls aged 11-18 yr residing in an urban slum in Delhi by both direct and indirect cyanmethaemoglobin methods, and the results were compared.
  
  
  RESULTS
  The mean haemoglobin levels for 888 whole blood samples estimated by direct and indirect cyanmethaemoglobin method were 116.1 ± 12.7 and 110.5 ± 12.5 g/l, respectively, with a mean difference of 5.67 g/l (95% confidence interval: 5.45 to 5.90, P<0.001); which is equivalent to 0.567 g%. The prevalence of anaemia was reported as 59.6 and 78.2 per cent by direct and indirect methods, respectively. Sensitivity and specificity of indirect cyanmethaemoglobin method were 99.2 and 56.4 per cent, respectively. Using regression analysis, prediction equation was developed for indirect haemoglobin values.
  
  
  CONCLUSIONS
  The present findings revealed that indirect cyanmethaemoglobin method overestimated the prevalence of anaemia as compared to the direct method. However, if a correction factor is applied, indirect method could be successfully used for estimating true haemoglobin level. More studies should be undertaken to establish agreement and correction factor between direct and indirect cyanmethaemoglobin methods.
authors.affiliation: Centre for Promotion of Nutrition Research & Training with Special Focus on North-East, Tribal & Inaccessible Population (Indian Council of Medical Research), New Delhi, India.
authors.forename: Priyanka Gupta
authors.initials: PG
authors.lastname: Bansal
authors.affiliation: Centre for Promotion of Nutrition Research & Training with Special Focus on North-East, Tribal & Inaccessible Population (Indian Council of Medical Research), New Delhi, India.
authors.forename: Gurudayal Singh
authors.initials: GS
authors.lastname: Toteja
authors.affiliation: Department of Food & Nutrition, Lady Irwin College, University of Delhi, New Delhi, India.
authors.forename: Neena
authors.initials: N
authors.lastname: Bhatia
authors.affiliation: Department of Environmental Studies, National Institute of Occupational Health, Ahmedabad, India.
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Gupta
authors.affiliation: Centre for Promotion of Nutrition Research & Training with Special Focus on North-East, Tribal & Inaccessible Population (Indian Council of Medical Research), New Delhi, India.
authors.forename: Manpreet
authors.initials: M
authors.lastname: Kaur
authors.affiliation: National Institute of Medical Statistics, New Delhi, India.
authors.forename: Tulsi
authors.initials: T
authors.lastname: Adhikari
authors.affiliation: Technical Division, National Accreditation Board for Testing & Calibration Laboratories, New Delhi, India.
authors.forename: Ashok Kumar
authors.initials: AK
authors.lastname: Garg
mesh_terms: D000293:Adolescent; D000740:Anemia / Q000097:blood* / Q000188:drug therapy / Q000453:epidemiology; D002648:Child; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage; D006454:Hemoglobins / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D007194:India; D007501:Iron / Q000008:administration & dosage; D008706:Methemoglobin / Q000031:analogs & derivatives* / Q000302:isolation & purification; D014805:Vitamin B 12 / Q000008:administration & dosage
chemical_list: D006454:Hemoglobins; C007169:cyanomethemoglobin; D008706:Methemoglobin; D005492:Folic Acid; D007501:Iron; D014805:Vitamin B 12