Past diagnostic methods have failed to isolate many newly identified viruses (NIVs), which is not surprising considering that those culture-based methods can be over 100-fold less sensitive than current molecular (PCR-based) tests [1,2,3,4] and that many new viruses do not grow in traditional culture at all.
So when an RT-PCR or PCR result cannot be confirmed by the culture of a virus from the same sample, that really doesn't mean more than...that.
Virus may be present, but our relatively insensitive culture techniques, which haven't really advanced in a long time, may just fail to get it growing.
Viral isolation by cell culture is really a dying art form. And it is a very lengthy, demanding and sometimes subjective art form at that requiring particularly skilled artistes.
- Templeton,K.E. et al. Improved diagnosis of the etiology of community-acquired pneumonia with real-time polymerase chain reaction. Clin Infect Dis 41, 345-351 (2005).
- van Kraaij,M.G.J. et al. Frequent detection of respiratory viruses in adult recipients of stem cell transplants with the use of real-time polymerase chain reaction, compared with viral culture. Clin Infect Dis 40, (2005).
- Garbino,J. et al. Lower respiratory viral illnesses: Improved diagnosis by molecular methods and clinical impact. Am J Resp Crit Care Med 170, (2004).
- Gunson,R.N., Collins,T.C., & Carman,W.F. Real-time RT-PCR detection of 12 respiratory viral infections in four triplex reactions. Journal of Clinical Virology(2005).