The Role of Serum Lactate Dehydrogenase in Etiological Diagnosis of Macrocytic Anemia

Abstract

Background: Macrocytic anemia is common and is characterized by decreased hemoglobin levels with elevated Mean Corpuscular Volume (MCV), due to a range of diseases and divided into Megaloblastic and Non-megaloblastic anemia. Serum vitamin B12 and folic acid tests are usually performed but they are limited by their low sensitivity and specificity. To confirm diagnosis of macrocytic anemia bone marrow examination is required but it is invasive procedure. Vitamin B12 and/or B9 deficiency leads to a defect in DNA synthesis leading to ineffective erythropoiesis and intramedullary hemolysis in patients of megaloblastic anemia, this leads to increased serum LDH (Lactate Dehydrogenase) and unconjugated bilirubin. Aims of study: This study was carried out to evaluate the role of serum LDH in the distinction between megaloblastic and non-megaloblastic anemia, and to study the correlation between serum LDH and MCV Patient and Methods: The study included 60 patients with non-regenerative macrocytic anemia (We exclude patients with regenerative macrocytic anemia because elevated reticulocytes leads us to hymolysis anemia or bleeding and it’s not a diagnostic problem(. Complete blood count, biochemical investigation, peripheral blood examination, reticulocyte count, bone marrow examination was performed in all cases Results: The most common cause of macrocytic anemia was Megaloblastic anemia (65%). The other causes were primary bone marrow disorders (35%). There was a significant difference in the mean values of serum LDH and MCV between two groups ( megaloblastic and non-megaloblastic anemia). When LDH>2076.5 IU/L, there is more probability of having megaloblastic anemia than non-megaloblastic anemia but when LDH>2076.5 and MCV>109.45 with bilirubin> 1.2mg/dl will must more probably not have non-megaloblastic anemia (the specificity was 100%), all three parameters combined together can be used as screening test to distinguish between the 2 groups of macrocytic anemia (megaloblastic and non-megaloblastic) without necessity of bone marrow aspiration in patients of non- regenerative macrocytic anemia. Present study had also shown that there were a positive relationship between serum LDH and MCV (r=+0.613).