Prevention of syncopal-type reactions after whole blood donation: a cluster-randomized trial assessing hydration and muscle tension exercise.

BACKGROUND: The prevention of presyncopal and syncopal reactions to whole blood donation is important for both the donor's safety and their retention as blood donors. The best strategy to achieve this remains debated. STUDY DESIGN AND METHODS: A prospective cluster-randomized trial comparing three hydration modes (500 mL of an isotonic drink, 500 mL of water, just before phlebotomy, or advice to drink [control arm]) coupled or not with light muscle tensing exercises, was carried out in mobile and fixed units of two regional blood centers in southeast France between January and July 2014. The main outcome was the cumulative incidence of presyncope (feeling faint) and syncope (fainting) at the donation site or in the 48 hours after leaving the site. Secondary outcomes were the cumulative incidence of these adverse events during donation, immediately after blood donation, or within 48 hours. RESULTS: Overall, presyncope or syncope occurred in 5.5% of the 4576 donors. Compared to controls, drinking 500 mL (isotonic solution or water) significantly reduced the rate of events (odds ratio [OR], 0.74; 95% confidence interval [CI], 0.55-0.99; p = 0.041) independently of muscle tensing exercise. Muscle tensing exercises significantly reduced syncopal-type reactions during the donation (OR, 0.64; 95% CI, 0.42-0.98; p = 0.041), and an isotonic drink significantly reduced delayed off-site syncopal-type reactions (OR, 0.62; 95% CI, 0.40-0.98; p = 0.040) and tiredness after donation (OR, 0.75; 95% CI, 0.59-0.94; p = 0.014). CONCLUSIONS: Drinking 500mL of water or isotonic drink close to phlebotomy is useful in preventing presyncopal or syncopal reactions in blood donors. Isotonic drinks have the advantage of preventing delayed reactions and tiredness after whole blood donation.

Flexible automated platform for blood group genotyping on DNA microarrays.

The poor suitability of standard hemagglutination-based assay techniques for large-scale automated screening of red blood cell antigens severely limits the ability of blood banks to supply extensively phenotype-matched blood. With better understanding of the molecular basis of blood antigens, it is now possible to predict blood group phenotype by identifying single-nucleotide polymorphisms in genomic DNA. Development of DNA-typing assays for antigen screening in blood donation qualification laboratories promises to enable blood banks to provide optimally matched donations. We have designed an automated genotyping system using 96-well DNA microarrays for blood donation screening and a first panel of eight single-nucleotide polymorphisms to identify 16 alleles in four blood group systems (KEL, KIDD, DUFFY, and MNS). Our aim was to evaluate this system on 960 blood donor samples with known phenotype. Study data revealed a high concordance rate (99.92%; 95% CI, 99.77%-99.97%) between predicted and serologic phenotypes. These findings demonstrate that our assay using a simple protocol allows accurate, relatively low-cost phenotype prediction at the DNA level. This system could easily be configured with other blood group markers for identification of donors with rare blood types or blood units for IH panels or antigens from other systems.

Failure and success of HIV tests for the prevention of HIV-1 transmission by blood and tissue donations.

French blood banks recently implemented nucleic acid testing (NAT) of all blood donations to reduce the risk of HIV transmission during the pre-seroconversion period. For tissue donation, HIV infection screening relies on HIV p24 antigen and anti-HIV-1 and 2 antibody detection. In this report, two related cases of infectious donations are described from a cornea donor during the preseroconversion window who was infected by an HIV antibody and NAT negative blood donor. After investigation, the blood donor was found to be herself in the preseroconversion window. Two months after donation, she was found to be HIV positive. The residual risk of HIV infectious blood donations since NAT has been introduced is estimated to be lower than one out of 2.5 millions. Individual NAT instead of minipool testing would not increase significantly the blood transfusion safety. In contrast, introduction of NAT should be considered to increase tissue donation safety as soon as such screening will be possible technically.