Laboratory approach to investigation of anemia with a focus on pyruvate kinase deficiency

Int J Lab Hematol. 2020 Jun:42 Suppl 1:107-112. doi: 10.1111/ijlh.13200.


Anemia is a major health burden worldwide and affects approximately one-third of world's population. It is not a diagnosis; it is a manifestation of an underlying pathophysiology leading to either decreased hemoglobin (Hb), hematocrit (Hct), or red blood cells (RBCs). Iron deficiency anemia is still the most common cause of anemia worldwide. The symptoms are usually due to the underlying compensatory responses to decrease in oxygen delivery to the tissues. Laboratory investigation should start with complete blood count (CBC), reticulocyte count (RC), and peripheral smear evaluation. Further testing depends on these indices, that is, iron parameters and hemoglobinopathies/thalassemia evaluation in microcytic hypochromic anemia, vitamin B12, and folic acid level in macrocytic anemia. Increased RC denotes adequate bone marrow response and points toward hemolytic process and vice versa. Anemia diagnosis can be complex and confusing for the practicing physician. This review tries to give a practical simplistic approach to the diagnosis, focusing mainly on the basic parameters, that is, CBC, RC, and peripheral smear etc. Moreover, we have also tried to provide an update on the pyruvate kinase deficiency, as there has been recent exciting development in the management of these patients.

Keywords: anemia; pyruvate kinase deficiency; reticulocytes.

Publication types

  • Review

MeSH terms

  • Anemia, Hemolytic, Congenital Nonspherocytic* / blood
  • Anemia, Hemolytic, Congenital Nonspherocytic* / diagnosis
  • Folic Acid / blood*
  • Hematocrit
  • Hemoglobins / metabolism*
  • Humans
  • Iron / blood*
  • Pyruvate Kinase / blood
  • Pyruvate Kinase / deficiency*
  • Pyruvate Metabolism, Inborn Errors* / blood
  • Pyruvate Metabolism, Inborn Errors* / diagnosis
  • Reticulocyte Count
  • Vitamin B 12 / blood*


  • Hemoglobins
  • Folic Acid
  • Iron
  • Pyruvate Kinase
  • Vitamin B 12

Supplementary concepts

  • Pyruvate Kinase Deficiency of Red Cells