Red Cell Distribution Width Index versus Red Cell Distribution Width as Discriminating Guide for Iron Deficiency Anaemia and Beta Thalassemia Trait .
Microcytic hypochromic anaemia is very common hematological abnormality in the clinical practice ( Snakar et;al. 2016 ) . Iron deficiency anaemia and beta thalassemia trait are the most common causes of microcytic hypochromic anaemia. As mentioned by the World Health Organization ( WHO ) estimates in 2004 , there were 273000deaths due to iron deficiency anaemia along with 19.7 million disability . Approximately 1.3 % cases were recorded globally in developing countries ( Kasseban et;al.2014 ) . Iron deficiency anemia is the most common nutritional disorder . This type of anemia is the final phase of a process that begins with exhaustion of iron stores and continues with iron depletion from other compartments that contain it compromising normal haematopoesis ( Wharton et;al. 1994 ) Beta thalassemia trait is the second most common cause of microcytic hypochromic anaemia . It is genetically determined disorder in which the defect of b globin gene results in decreased production of hemoglobin A1 ( Sliman et;al. 2004 ) The differentiation between Iron deficiency anemia and Beta thalassemia trait is important because of two main reasons . First , because hemoglobin will not improve in beta thalassemia trait if it is misdiagnosed as Iron deficiency anemia and unnecessary iron being prescribed by the attending physician ( Vehapoglee et;al. 2014 ) . The second grave reason is that misdiagnosed beta thalassemia trait as Iron deficiency anemia may get married to a beta thalassemia trait , resulting in homozygous or thalassemia major in the offsprings ( Tripathi et;al. 2015) Ideally one needs a battery of tests including detailed peripheral blood picture , HBA2 estimation , serum iron , TIBC , serum ferritin and transferrin saturation to differentiate Iron deficiency anemia from beta thalassemia trait clearly (Bordbar et;al. 2015 ) . But all these investigations are either not available in all clinical setup or they are relatively time consuming and need expensive techniques ( Natios et;al. 2007 ). Derived indices showed that RDW is the first index of the routine blood count to become abnormal during the development of Iron deficiency anemia ( McCulre et;al. 1985 ) . It quantitatively measures red blood cells size. variation computed directly from the RBCs histogram and is calculated as standard statistical value , the coefficient of variation of the volume distribution ( Verma et;al. 2015 and Plengsures et;al. 2015) . RDW is high in Iron deficiency anemia because there is a wide variation in red cell size . in beta thalassemia trait , the red cells are all the same size , there is virtually no variation ,so RDW is low ( Park et;al.2009 ) . Another red cell discriminate function , RDWI had been proven to be reliable discrimination index in the differentiation between Iron deficiency anemia and beta thalassemia trait ( Ismail et;al.2016 ) . It can be easily calculated as ( MCV in ( Fl) x RDW / RBCs in (million per microlitre ) ) quotient more than 220 suggest Iron deficiency anemia , less than 220 suggest beta thalassemia trait. RDWI provide valiable help to the attending physician as all discriminating factors including RBCs count , MCV and RDW are incorporated in its formula ( Jayabose et;al. 1999 ) .
Study Type
OBSERVATIONAL
Enrollment
100
The study will conducting on 100 patients of microcytic hypochromic anaemia who recruited from the hematology outpatient clinic , Assiut University Children Hospital . Beside history and clinical examination , the studied cases will be subjected to the following investigations Complete blood count ( CBC ) with comparison of MCV , RBCs count , RDW and RDWI . Determination of serum ferritin , serum iron and total iron bending capacity ( TIBC ) . HB electrophoresis . Patient with HBA2 more than 3.2 % are identified as beta thalassemia trait and patients with serum ferritin less than 12 ng / ml are identified as IDA cases. Validity of both discrimination indices are evaluated by calculating there sensitivity , specificity , positive predictive value , negative predictive value and Youden index ( YI ) Based on statistical criteria in ideal test should have high sensitivity and specificity and Youden index.
Diagnostic comparison of both the RDWI and RDW in the differentiation of Iron deficiency anemia and Beta thalassemia trait
RDW is high in Iron deficiency anemia because there is a wide variation in red cell size . in beta thalassemia trait , the red cells are all the same size , there is virtually no variation ,so RDW is low ( Park et;al.2009 ) . Another red cell discriminate function , RDWI had been proven to be reliable discrimination index in the differentiation between Iron deficiency anemia and beta thalassemia trait ( Ismail et;al.2016 ) . It can be easily calculated as ( MCV in ( Fl) x RDW / RBCs in (million per microlitre ) ) quotient more than 220 suggest Iron deficiency anemia , less than 220 suggest beta thalassemia trait.
Time frame: Baseline
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