The Chhattisgarh state screening programme for the sickle cell gene: a cost-effective approach to a public health problem.

In India, the Chhattisgarh State screening programme for sickle haemoglobin focuses on children aged 3-15 years and has screened over 1,050,440 subjects over the last 6 years. Commencing in the District around the capital Raipur, this programme has now completed screening in 7 of the 27 Districts of Chhattisgarh State. Screening is initially performed by solubility tests on fingerprick samples in the field and those with positive tests have venipunctures for haemoglobin electrophoresis. The frequency of the sickle cell trait was 9.64 % and of the SS phenotype 0.29 % with only two Districts in Hardy-Weinberg equilibrium, most Districts showing an excess of the SS 'phenotype' most readily explained by symptomatic selection. The estimated costs were US$0.28 (solubility tests alone) and US$0.60 (haemoglobin electrophoresis). Of the social groupings commonly used in India, the OBC's (other backward classes) had the highest frequencies of the sickle cell gene mutations, followed by the Scheduled Tribes and the Scheduled Castes. The objectives of the programme were the detection of sickle cell disease for prospective clinical management and of the sickle cell trait for purposes of genetic counselling. The former objective is being met for diagnosis although the success of referral to clinic services requires audit. The objective of genetic counselling is compromised by the failure of the screening test to detect other genes of potential clinical significance such as HbD Punjab and the beta thalassaemia trait. Despite these exceptions, the detection of HbS appears relatively robust and could be another condition factored into the traditions of partner selection amongst the underprivileged communities of this state. Overall, the Chhattisgarh programme seeks to address the daunting challenges of large populations carrying the sickle cell gene and maybe a useful model for elsewhere.