Interferon assay as a viral diagnostic test.

The early production of interferons (IFNs) following viral infection has led to their detection being investigated as a method of diagnosis of such infections. The assay described here for alpha-IFN can be completed in one day and therefore has advantages over previously used bioassays. However, because production of IFN is transient, collection of samples must be soon after the onset of illness. For this reason the assay is more useful in cases where patients are seen early after the onset of symptoms. We have been looking at several such groups; the one reported here is children admitted to a paediatric infectious disease unit. 24/34 sera where a virus was found were positive for IFN and 14/52 where no virus was isolated. Control sera and those from patients with a bacterial infection were negative for IFN. We feel that the test is useful for certain groups of patients and are continuing to assess the assay for inclusion as a routine diagnostic test.