Simple spectrophotometric determination of haptoglobin-haemoglobin complex in haemolysed samples.

The concentration of haptoglobin-haemoglobin complex in haemolysed serum was measured by reducing the sample with sodium hydrosulphite. The absorption spectra of serum before and after sodium hydrosulphite treatment were compared, and the absorbance change was used to determine the amount of haemoglobin in the sample. By analysing the difference absorption spectra of various types of haemoglobin-containing samples, it was also possible to determine the haptoglobin level in samples haemolysed severely beyond their haemoglobin-binding capacities. When the present methods are used, along with the spectrophotometric method for free haptoglobin, one can measure separately the amounts of free haptoglobin, haptoglobin-haemoglobin complex, and free haemoglobin in samples with varying degrees of haemolysis.