HPV reports are easy to read, with test results reported as negative or positive, and some hospital laboratories reporting test results as undetected or detected. A positive test result indicates the presence of the subtype of HPV infection, while a negative result means that the subtype of virus is not detected. Other hospitals directly classify the test viruses and report the test results as either no infection in the high-risk group or an infection in the high-risk group of a certain subtype. There are more than 130 subtypes of HPV viruses that have been medically discovered, but hospitals do not test for all subtypes, and monitor for high-risk or low-risk viruses that are necessary. Also, the number of types tested varies from hospital to hospital, and the results are determined by testing the DNA of the virus.