lmportance of donor selection suwey in infectious disease prescreening: experience a t a blood bank in Bogota, November-December, 1996

Abstract

Decreasing the risk of acquiring a transfusional disease depends on a careful donor selection by means of surveys, serological screening and, more recently, viral inactivation. Surveys allow the detection of individuals who might be carriers of infections not detected by serological screening (window period), and, therefore, their usefulness depends, among others, on the type of donor and hislher motivation for doning. In some countries, donors differ from general population in aspects such as social characteristics, doning frequency and, above all, their low risk in blood transmitted infections. In Colombia, nevertheless, around 80% of the blood comes from replacement, and rnany times, forced donors who do it on a non regular basis. In order to assess the survey's usefulness and the donors' selection process, and to establish the prevalence of blood transmitted infections subject to screening, a descriptive study was carried out of donors' records who approached a blood bank in Bogotá during November and December, 1996. 414 donors' surveys and their corresponding serological results were reviewed. We assessed if the survey included or not questions related to risk factors for blood transmitted infections, the percentage of questions answered in each case, the relation between donors' answers and their acceptance or refusal to donning. sociodemographic characteristics, as well as reaction to antibodies against HIV, HCV, Treponema pallidum, Trypanosoma cruziand HBsAg. We found that questions regarding tattoos, use of intravenous drugs and types of sexual conduct, among others, were not included in the survey 90% of the questions were answered in the 414 surveys, but questions on sex. occupation and marital status appeared more frequently unanswered. 65% of donors were men and the average age was 32. From the total number of donors, 325 (78.5%) did not report any risk factor for blood donation. and out of these, 52 (16%) were seroreactive to some of the markers. while among the 89 donors who reported some risk factor, we found 10 seroreactive. 15% of seroreactivity to al1 markers such as HIV, HBsAg, HCV, T pallidurn and T cruzi was three times higher than the national average (5.2%) in 1996 and to that reported in other studies. The main risk factors reported by reactive donors were: previous transfusions, chest film and poor health at the moment of donation. There were no statistically significant differences in sociodemographic characteristics between reactive and non reactive donors. The survey aims at selecting donors with the least risk factors, thus protecting both donors and recipients' health. and using blood bank's resources at their best.