A titer is a laboratory test that measures the presence and amount of antibodies in blood. A titer may be used to prove immunity to disease. A blood sample is taken and tested.
If the test is positive (above a particular known value) the individual has immunity. If the test is negative (no immunity) or equivocal (not enough immunity) you need to be vaccinated.
A Titer Lab Report is generated by the lab that tested the blood sample. The Titer Lab Report must include the test type, exact values, signature, and date.