Alternatively, influenza virus detection may be achieved by the spin amplification technique in which viral inoculum is spun onto specially prepared cell monolayers to enhance viral uptake and the infected cells are then specifically stained by IF after 24 -48 hours of incubation. This technique, among others, has been utilised successfully in this laboratory in recent years. Clinicians are reminded that the type of specimen and the timing of specimen collection is of paramount importance for effective viral diagnosis. Swabs should be placed in viral transport medium which the VRL can supply on request and sent to the laboratory within 24 hours. A throat wash is obtained by getting the patient to gargle with approximately 10 mls of normal saline.
Influenza virus shedding normally declines rapidly within the first few days of illness.
Therefore specimens for viral isolation and antigen detection should normally be collected from 1 - 3 days after the onset of symptoms. Since influenza virus detection may not always be successful for the reasons already outlined above, antibody detection may be achieved by obtaining a seroconversion or fourfold rise in the patient's antibody levels from acute and convalescent phase sera. Therefore it may be helpful to have a 10 ml specimen of clotted blood taken at the acute phase of illness and a further blood specimen taken during convalescence. His wife and child had been ill in the previous week. There was a foul stench off his breath.