Chapter 1
Chapter 1
Diagnostic Performance of Red Blood Cell Indices in the Differential Diagnosis of Iron Deficiency Anemia and the Thalassemia Trait in Chile: A Retrospective Study
Abstract: Background: Iron deficiency anemia and the beta-thalassemia trait are two main causes of hypochromic-microcytic anemia worldwide. Researchers have described many red blood cell indices as screening tests for presumptive differentiation, based on differences observed in complete blood count data for each condition. There are few beta-thalassemia trait reports in Chile, and neither laboratories nor clinical staff have widely used these indices. Objective: The objective of this study was to evaluate the diagnostic performance of twenty-nine red blood cell indices in one hundred eighty-two patients (fifty-one beta-thalassemia trait and one hundred thirty-one iron deficiency anemia) and compare complete blood count results in both groups. Methods: A retrospective search was carried out in the Laboratory Information System between January twenty twenty-one and February twenty twenty-four to collect results from complete blood count, and twenty-nine red blood cell indices were calculated for each patient. Then, sensitivity, specificity, positive predictive value, negative predictive value, Youden's index, positive likelihood ratio, negative likelihood ratio, and diagnostic accuracy were calculated using MedCalc. Results: The Green and King, Wongprachum, and Keikhaei indices showed the best discriminatory power with Youden index values of zero point nine two three, zero point nine zero eight, and zero point eight nine six, respectively, and significant differences were observed in all complete blood count parameters between beta-thalassemia trait and iron deficiency anemia patients (P is less than zero point zero zero one). Conclusions: The Green and King, Wongprachum, and Keikhaei indices showed the best performance; therefore, they can be used as screening for the differential diagnosis between beta-thalassemia trait and iron deficiency anemia in order to improve diagnosis given the important therapeutic and epidemiological implications. In this way, clinical laboratories could have a main role in the investigation of these patients.
One. Introduction
One. Introduction
The World Health Organization defines anemia as a condition in which the number of red blood cells or the total hemoglobin concentration within them is lower than normal in the blood. The diagnosis cut-off point varies based on sex, age, and physiological condition, impacting an estimated one point six two billion people worldwide, with a higher prevalence in developing countries compared with developed ones. The most common way to group morphological anemias is by their Mean Corpuscular Volume in microcytic, normocytic, and macrocytic. Among microcytic anemias, thalassemias and iron deficiency anemia are the most frequent causes worldwide. In beta-thalassemia,
there is a partial or total decrease in the synthesis of beta-globin chains in hemoglobin due to genetic mutations. Currently, the following conditions are recognized: beta-thalassemia trait, beta-thalassemia intermedia, and beta-thalassemia major. Beta-thalassemia trait is caused by a heterozygous mutation and has no symptoms. It can be identified by its specific hematological features, which are confirmed by hemoglobin electrophoresis (hemoglobin A two fraction greater than three point five percent). On the other hand, iron deficiency anemia is the cause of approximately fifty percent of anemias worldwide and mainly affects children and women of childbearing age. Although both anemias are of the microcytic type, beta-thalassemia trait has a greater degree of decrease in Mean Corpuscular Volume, a smaller decrease in hemoglobin, and a higher erythrocyte count. Furthermore, studies have demonstrated a greater prevalence of basophilic stippling in beta-thalassemia trait compared with iron deficiency anemia. Based on these findings, researchers have described several discriminatory red blood cell indices to differentiate between beta-thalassemia trait and iron deficiency anemia presumptively. These indices can serve as screening tests for more specific and expensive studies that determine the cause of anemia.
In Chile, specialist doctors at the tertiary level typically diagnose beta-thalassemia trait, but few studies present a series of diagnosed cases or evaluate the performance of discriminatory red blood cell indices described in the specialized literature. Furthermore, the majority of the limited published studies focus on isolated cases of beta-thalassemia trait and/or beta-thalassemia major in pregnant patients and/or their offspring, which means the discriminatory power of these red blood cell indices has not been estimated in our population.
There are various equations for differentiating beta-thalassemia trait from iron deficiency anemia. Each of these differentiators possesses unique sensitivity, specificity, and Youden indices, leading to a variety of reported results. The present study is innovative because it compares twenty-nine differential equations simultaneously. Many related research studies used fewer equations than our study to diagnose beta-thalassemia trait from iron deficiency anemia. Furthermore, this study was the first in the region. Therefore, given this lack of information at the national level, the present study aimed to evaluate the ability of twenty-nine differential equations consisting of simple blood parameters to separate individuals with beta-thalassemia trait from those with iron deficiency anemia by calculating sensitivity, specificity, positive predictive value, negative predictive value, Youden's index, positive likelihood ratio, negative likelihood ratio, and diagnostic accuracy. Therefore, the two objectives of this study were to evaluate the diagnostic performance of twenty-nine red blood cell indices in patients diagnosed with beta-thalassemia trait and iron deficiency anemia and to compare complete blood count values between both groups of patients.