Greetings! In NH NPIP testing also includes the Avian Influenza (AI) test. It's all done from the same blood sample at the NH Veterinary Diagnositics Lab at UNH.
The NPIP test isn't really a benefit or concern with egg sales for consumption. Concerns to consider there are about proper hygiene and egg handling, cleanliness, and storage, The NPIP program is about attempting to control and monitor flock and, especially, inter-flock contamination and disease transference. It's really important for (and because of) large producers. It serves to monitor them and protect them from loss.
I've begun selling hatchery chicks at the chicken swaps and it was a requirement of this. Any that I get are from tested hatcheries. I have yet to purchase any older chickens. Currently I'm drooling over Jubilee Orpingtons on the Green Fire Farm site but am wishing they were sexed.....