Medschool MCQ 3:

Medschool MCQ 3:

A 23yrs female presented with jaundice and pallor for 2 months.Her peripheral blood smear shows the presence of spherocytes.The most relevant investigation to arrive at a diagnosis is which of the following?(AIIMS May2012)

a) Tests for PNH.

b) Osmotic fragility test.

c) Coombs test.

d) Reticulocyte count.

Spherocytes

Explanation:

The correct answer is (c)Coombs test.

The presence of spherocytes can be seen in:

-Hereditary spherocytosis.

- Autoimmune hemolytic anaemia.

- G6PD deficiency.

- Burns

- Hemolytic disease of newborn

Now coming to individual options:

* PNH is not a cause for presence of spherocytes

* Osmotic fragility is increased with spherocytes.So it does not provide any additional information about the disease causing spherocyte formation.

* Reticulocyte count is expected to be raised in hemolytic anaemia suggested by jaundice and pallor

* Coombs test will be positive in autoimmune hemolytic anaemia but negative in hereditary spherocytosis,thus it helps to differentiate between these two conditions.