Ammonium improves elution of fixed dried blood spots without affecting immunofluorescence assay quality

OBJECTIVE: To solve the problem of fixed dried blood spot elution without damaging IgG antibodies. METHODS: The minimum effective concentration of liquid ammonium (NH3 ) in a PBS solution, which was found to elute fixed blood, was determined. By using a dilution series, the effects of NH3 on IgG antibody quality were assessed using immunofluorescence assays. RESULTS: The minimum effective concentration of 0.2% NH3 has no detectable effects on IgG quality. CONCLUSION: Ammonium greatly improves blood elution from fixed DBS while maintaining IgG antibody quality. These results are encouraging and provide a basis for further testing of the efficacy of ammonium in different situations as well as its effect on other compounds.