FREQUENCY OF PYRUVATE KINASE (PK) DEFICIENCY IN NEONATES WITH HAEMOLYTIC ANAEMIA

PK Deficiency in Neonates with Haemolytic Anaemia

Abstract

Objective: To determine the frequency of pyruvate kinase deficiency in neonates presenting with haemolytic anaemia.

Study Design: Cross sectional descriptive study.

Place and Duration of Study: Haematology department, Armed Forces Institute of Pathology, Rawalpindi (AFIP) from Jan 2011 to Jan 2012.

Material and Methods: Study was done in collaboration with neonatology department of Military Hospital. Informed consent from parents of neonates was obtained. Two hundred and twenty five neonates with haemolytic anaemia based on low haemoglobin (<14g/dl), raised reticulocyte counts (>5%) and indirect hyper bilirubinaemia (as per CDC nomogram for evaluation of hyper bilirubinaemia in term neonates) were selected. Qualitative pyruvate kinase enzyme assay was done using Bio vision PK assay kit. Estimation of enzyme was based on generation of pyruvate by addition of substrate with change in optical density (OD) of sample in presence of enzyme. Dilution of standard as recommended by manufacturer was made and standard graph was plotted. The OD was measured using wave length of 570 nm at two points (start and at 25 min). Cut off limit of less than 25% activity was considered positive for pyruvate kinase deficiency. Confirmation was done by running in parallel negative and positive controls (provided).

Results: Seven (3.1%Confidence Interval: ±3.33) out of 225 patients were found deficient. Among these 4 were male and 3 were female neonates. The age range was between 1 to 3 weeks. The mean age of presentation was 1.89 ± (0.832) weeks.

Conclusion: We conclude that pyruvate kinase deficiency is not uncommon in our setup and all patients with congenital non-spherocytic haemolytic anaemia where cause cannot be established should be screened for pyruvate kinase deficiency.