1. Adequate specimens means 2 specimens collected 24-48 hours apart and within 14 days of onset of paralysis.
2. The specimen arriving at the laboratory must be of adequate volume approximately 8-10 grams), have appropriate documentation (laboratory request form) and be in “good condition” (evidence that the reverse cold chain was maintained (presence of ice or temperature indicator), no leakage, no desiccation).
3. Compatible cases indicate surveillance failures and must be monitored for clustering in space and time.