Fainting and hemolysis during blood sampling in youngsters: Prevalence study

ObjectiveTo assess the incidence of fainting and hemolysis in taking blood samples from adolescents in a school setting.DesignA cross-sectional school-based survey. All blood samples and data were collected during September and October 2005.SubjectsA community sample of 869 youngsters attending third grade secondary education in 14 secondary schools in the Flemish province of Antwerp, Belgium (mean age: 17.3 years, ±1.2 years).MeasurementsFasting blood samples were obtained on-site for measurement of levels of glucose, high density lipoprotein cholesterol and triglycerides. The incidence of fainting and hemolysis was assessed.ResultsIn 60% of the total sample a blood sample was taken, 15% refused. In the remaining 25%, taking a blood sample was not possible due to problems in drawing blood from the vein (4%) or not fasting (21%). The incidence of fainting was 2.5%. Hemolysis occurred in 2.4% of the blood samples.ConclusionWhen taking blood samples in this age group, there seems to be a great willingness to participate. Precaution should be taken though when taking blood samples in youngsters. In this study, about 1 in 40 students fainted. When blood samples are taken on-site and transported to a laboratory, an incidence of hemolysis of 2.4% should be taken into account.