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Notes

The precision of various methods for estimating haemoglobin concentration may differ considerably.  The cyanohaemoglobin method has been the standard method used in haematological studies for a number of decades.  However the alkaline haematin D-575 method has been adapted for studies in fish haematology and it has been reported that the cyanohaemoglobin method may yield lower haemoglobin concentrations than those obtained with the alkaline haematin D-575 method.  It has been suggested that the cyanohaemoglobin method may have other disadvantages; primarily that the reagent contains cyanide which is toxic, and that the end-product is light labile.

For the purposes of this module, the cyanohaemoglobin method, as the most widely used procedure in determining haemoglobin concentration in fish (and in other animals), is described.

Definitions

ANAEMIA:  A condition characterised by a deficiency of functional haemoglobin, packed cell volume and/or erythrocytes. The more important types of anaemia in fish are: normocytic anaemia caused by acute haemorrhaging, bacterial and viral infections, and metabolic diseases resulting in red cell destruction; microcytic anaemia due to chronic haemorrhaging, e.g. caused by external parasites, iron deficiency and the deficiency of certain haematopoietic factors; and macrocytic anaemia (e.g. absence of juvenile cells; too many mature cells) resulting from an increase in haematopoietic activity in the spleen and kidney.