MxA protein in capillary blood of children with viral infections

Capillary blood of febrile children was lysed by using a lysis buffer containing ascorbic acid. MxA quantitation was performed by an immunochemiluminescent assay. The MxA values were significantly higher in capillary blood of infants with viral infections due to adenovirus (n = 5), rotavirus (n = 15), or respiratory syncytial virus (n = 28), than in capillary whole blood from infants with bacterial infections (n = 6) and healthy control patients (n = 20). A strong correlation was found between the MxA values in capillary whole blood and peripheral whole blood (r' = 0.86, P < 0.0001, n = 48). The MxA values found at these two sites were compared with the levels of IFN-alpha obtained by a dissociation enhanced lanthanide fluoroimmunoassay. A correlation between these two values was found. The results show that the combination of collection of blood by finger prick and specific immunochemiluminescent assay for MxA protein measurement may be of value for the diagnosis of viral infections in children.