Serum cholesterol binding reserve and its ratio to serum cholesterol in first degree relatives of patients with ischaemic heart disease.

Serum total cholesterol and serum cholesterol binding reserve (SCBR) were estimated in 50 healthy subjects and 25 cases with ischaemic heart disease (IHD) and their seventy asymptomatic first degree relatives. In normal subjects mean values of SCBR tended to expand with increasing levels of serum cholesterol, while this relationship was reversed in cases with IHD. The relatives showed a direct correlation between serum cholesterol and SCBR upto serum cholesterol level of 220 mg/dl, but the correlation was lost beyond this level. The critical levels for predicting risk of IHD were 30 mg/dl for SCBR and 8 for cholesterol: SCBR ratio. The latter was found to be a more sensitive index for predicting the risk of IHD as compared to SCBR alone.