Our data showed that p16INK4A FCM (an in vitro diagnostic device, IVD) can be used to quantitatively and precisely determine the cervical p16INK4A expression level, by which both age‐dependent physiological and infection‐induced aberrant expression of p16INK4A can be measured; therefore, the related intracellular molecular changes upon HPV infection (as Pap is still normal) can be surveilled. The gene discussed is CDKN2A; the disease is infection.