Samples are concentrated, then cultured in L20B (mouse cells with polio receptors added) and human rhabdosarcoma (RD) cells) to screen for either non-polio enteroviruses (very common). Samples which are L20B +ve (i.e. likely have polio) are then further passaged into RD for virus growth and RT-PCR to get the polio serotype and intratype.
Many places which have the resources will then do a full sequence on any +ve samples as well to determine whether there is community transmission since this will show up as a number of related viruses which are all related to each other more closely than they are to the parent strain.
London screening frequently sees unrelated OPV strains which are due to people who have recently been vaccinated with OPV in places where that is still the preferred vaccine, what is concerning here is that the deep sequencing shows that there appears to be some person to person spread of a vaccine derived strain.
To answer your question, this is a highly sensitive and extremely specific test. Details no doubt available in the open literature somewhere.
Many places which have the resources will then do a full sequence on any +ve samples as well to determine whether there is community transmission since this will show up as a number of related viruses which are all related to each other more closely than they are to the parent strain.
London screening frequently sees unrelated OPV strains which are due to people who have recently been vaccinated with OPV in places where that is still the preferred vaccine, what is concerning here is that the deep sequencing shows that there appears to be some person to person spread of a vaccine derived strain.
To answer your question, this is a highly sensitive and extremely specific test. Details no doubt available in the open literature somewhere.