Volume: 8 Issue: 2
Year: 2020, Page: 38-46, Doi: https://doi.org/10.47799/pimr.0802.10
Introduction: Clinical manifestations of vitamin B12 deficiency are mostly non-specific. An entity called subclinical deficiency has become popular where the need has arisen to perform costly investigations which indicate functional deficiency of vitamin B12 even when vitamin B12 levels are normal. These factors pose a challenge in planning management of patients.
Aims and objectives: The study was conducted as an attempt to identify affordable and credible laboratory indicators of vitamin B12 deficiency which can be used as screening tests before choosing patients for further evaluation or treatment.
Material and Methods: This was a time bound cross-sectional study where 100 adult patients who had undergone the following investigations were randomly chosen: Complete Blood Count with red cell indices, serum bilirubin and serum vitamin B12 levels. The sensitivity, specificity and predictive values (positive-PPV and negative-NPV) of the variables that could hypothetically identify vitamin B12 deficiency, both individually or in combinations were calculated and compared.
Results and conclusion: Hemoglobin, MCV (Mean Corpuscular Volume), MCH (Mean Corpuscular Hemoglobin), platelets and bilirubin were not equally distributed between vitamin B12 deficient and normal groups(p values for these variables were 0.029, 0.000, 0.000, 0.003 and 0.029 respectively).When these variables were tested individually and in combination, the combination of [MCV=95 fl or MCH=30 pg or Platelets =1.4 lakh/µl or Bilirubin =1 mg/dl] had sensitivity of 68.2%, specificity of 85.7%, PPV of 78.9% and NPV of 77.4%. This proposed combination used as a screening test has potential for wide application considering its simplicity and cost advantage.
Keywords: Cobalamin deficiency, Erythrocyte Indexes, Mean Corpuscular Hemoglobin, Mean Corpuscular Volume, Red Cell Indices
1. Carmel R. Current concepts in cobalamin deficiency. Annu Rev Med 2000;51:357-75
2. Dali-Youcef N, AndrèsEAn update on cobalamin deficiency in adults. QJM. 102:17,.2009
3. Carmel R. Biomarkers of cobalamin (vitamin B-12) status in the epidemiologic setting: a critical overview of context, applications, and performance characteristics of cobalamin, methylmalonic acid, and holotranscobalamin II. Am J ClinNutr. 2011;94(1):348S–358S. doi:10.3945/ ajcn.111.013441
4. Pennypacker LC, Allen RH, Kelly JP, Matthews LM, Grigsby J, Kaye K, Lindenbaum J, Stabler SP. High prevalence of cobalamin deficiency in elderly outpatients. J Am Geriatr Soc. 1992;40 :1197–1204.
5. Aslinia F, Mazza JJ, Yale SH. Megaloblastic anemia and other causes of macrocytosis [published correction appears in Clin Med Res. 2006 Dec;4(4):342]. Clin Med Res. 2006;4(3):236–241. doi:10.3121/cmr.4.3.236
6. Carmel R, Green R, Rosenblatt DS, Watkins D. Update on cobalamin, folate, and homocysteine.Hematology. 2003:62–81
7. Chan CWJ, Liu SYH, Kho CSB, et al. Diagnostic clues to megaloblasticanaemia without macrocytosis. Int J Lab Hematol. 2007;29 :163–171
8. Sarma PR. Red Cell Indices. In: Walker HK, Hall WD, Hurst JW, editors. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Boston: Butterworths; 1990. Chapter 152. Available from: https:/ /www.ncbi.nlm.nih.gov/books/NBK260/
9. Bhatia P1, Kulkarni JD, Pai SA. Vitamin B12 deficiency in India: mean corpuscular volume is an unreliable screening parameter. Natl Med J India. 2012 Nov-Dec;25(6):336-8.
10. Matos JF, Dusse LM, Borges KB, de Castro RL, Coura-Vital W, Carvalho Md. A new index to discriminate between iron deficiency anemia and thalassemia trait. Rev Bras HematolHemoter. 2016;38(3):214–219. doi:10.1016/ j.bjhh.2016.05.011
11. Suad M. AlFadhli, Anwar M. Al-Awadhi, Doa’aAlKhaldi, Validity Assessment of Nine Discriminant Functions Used for the Differentiation between Iron Deficiency Anemia and Thalassemia Minor, Journal of Tropical Pediatrics, Volume 53, Issue 2, April 2007, Pages 93–97, https:// doi.org/10.1093/tropej/fml070
12. Park K. Screening for disease. In: Park’s Textbook of Preventive and Social Medicine, 25th ed. Pages 152-153.
13. Singla R, Garg A, Surana V, Aggarwal S, Gupta G, Singla S. Vitamin B12 deficiency is endemic in Indian population: A perspective from North India. Indian J EndocrMetab 2019;23:211-4
14. Pautas E, Cherin P, De Jaeger C, Godeau P. Vitamin B 12 deficiency in the aged. Presse Med1999;28:1767-70
15. vanAsselt DZ, Blom HJ, Zuiderent R, Wevers RA, Jakobs C, van den Broek WJ, et al. Clinical significance of low cobalamin levels in older hospital patients. Neth J Med 2000;57:41-9
16. Oh R, Brown DL. Vitamin B12 deficiency. Am Fam Physician. 2003 Mar 1;67 (5):979-86.
17. Savage DG, Lindenbaum J, Stabler SP & Allen RH (1994): Sensitivity of serum methylmalonic acid and total homocysteine determinations for diagnosing cobalamin and folate deficiencies. Am J Med 96: 239–246.
18. Nagao T, Hirokawa M. Diagnosis and treatment of macrocytic anemias in adults. J Gen Fam Med. 2017;18(5):200–204. Published 2017 Apr 13. doi:10.1002/ jgf2.31
Deepak Kumar P, Makwana D, Wadkar P . Indigenous indicators of vitamin B12 deficiency. Perspectives in Medical Research 2020; 8 (2):38-46. DOI : 10.47799/pimr.0802.10