What is a Titer?
A Titer is a blood test that checks your immune status to vaccinations or diseases you may have received in the past. There are two types of immunity a person can have:
1. Active Immunity
- The body’s immune system produces antibodies and cellular immunity which usually lasts for many years to a lifetime.
- Develops from surviving infection or by vaccination
- Every individual varies in response and production of antibodies
2. Passive Immunity
- Immunity transferred from one to another
- Develops from mother to infant or by blood product such as immune globulin
- This immunity usually only offers temporary protection during a period of weeks to months
There are several types of Titer testing and they are as folows:
Hepatitis A Titer
Hepatitis A is a contagious liver disease that results from infection with the Hepatitis A virus. The Hepatitis A titer is used to check immunity from previous infection or vaccination.
A Titer for Hepatitis A can be used in specific circumstances to reduce the costs of vaccination people who are already immune to Hepatitis A, such as:
- Persons who were born in parts of the world with a higher prevalence of Hepatitis A infection, such as many 3rd world countries
- Anyone who believes to have been exposed to Hepatitis A infection
- Certain adolescents and adults in population groups such as American Indians, Alaska Natives, and Hispanics
- Adults 40 years of age and older
The Vaccine Center and Travel Medicine Clinic offers a test to determine if a person has a recently acquired Hepatitis A infection called Hepatitis A Igm Antibody; or a test to determine if immunity is present due to previous vaccination or infection called Hepatitis A Total Antibody Test.
Hepatitis B Titer
Hepatitis B Virus is an infection that is an established cause of acute and chronic hepatitis and cirrhosis of the liver. Hepatitis B is spread through contaminated blood and bodily fluids. The Hepatitis B Antibody titer is used to check immunity from previous vaccination for persons who are at increased risk of exposure to Hepatitis B.
The Hepatitis B test used to check immunity following Hepatitis B vaccine or previous Hepatitis B infection is called Hepatitis B surface Antibody Titer. This blood test measures the level of immunity and determines if the results indicate a protective level of immunity or indicate the need for booster doses of Hepatitis B vaccine.
Testing for immunity following vaccination should be considered for persons who may be at increased risk of contracting Hepatitis B infection such as:
- Health care workers or public safety workers who have direct patient contact.
- Chronic hemodialysis patients
- Immunocompromised persons (persons who may have a weakened immune system)
- Persons with HIV infection
- Sex partners who have been exposed to Hepatitis B infected person
- Infants born to Hepatitis B infected mother
An MMR Titer is a blood test to check immunity for Measles, Mumps, and Rubella. Infection with any of the 3 diseases may have serious implications to a person’s health. The vaccine for MMR has been given routinely in the United States since 1971. It was not until 1989 that the Advisory Committee on Immunization Practices recommended 2 doses of MMR for each individual. There was a large increase in Measles cases in the US in 2008 due to importation of Measles from other countries and from unvaccinated individuals.
Due to the potential likelihood of inadequate vaccine coverage and risk of disease transmission and outbreaks, many schools and employers require persons to show proof of 2 MMR Vaccines or proof of immunity to MMR for safety reasons. Colleges and post-high school educational institutions are potential high-risk areas for Measles, Mumps, and Rubella infection due to the large concentrations of susceptible persons. An MMR titer may prove immunity due to previous infection or previous MMR vaccination. All persons who work in medical facilities are at a higher risk of exposure and should have evidence of immunity to measles, mumps, and rubella or 2 doses of live MMR vaccines.
Persons who travel internationally are also at increased risk of exposure to measles. All travelers should have either adequate vaccination or evidence of immunity through an MMR titer.
Varicella (Chicken Pox) Titer
Varicella (Chicken Pox) is a member of the herpes virus group. The primary infection results in Chicken Pox. Later in life, recurrent infection may emerge as Shingles. It is important for all individuals to know his/her status of immunity against the Varicella virus to protect those individuals form the higher risk of complications from acquired Varicella. A Varicella Titer will detect whether a person is immune to Varicella due to previous infection or immunization.
Varicella Titer testing should be performed for:
- Health Care personnel who are uncertain of their Varicella history
- Pre Vaccination screening for adults who are uncertain of their Varicella history
- Immigrants to the United States applying for Permanent Residency who must show proof of Varicella disease
- Any person who lacks evidence of appropriate vaccination coverage
Rabies is a progressive fatal disease caused by a virus spread through rabid mammal. Laboratory testing can be used to evaluate the immune response to rabies antigen found in the vaccine. This laboratory test, called a Rabies Titer, is generally used for persons who have an occupational risk of rabies virus exposure, such as veterinarians or rabies virus laboratory workers.
The laboratory test may also be used for persons concerned about his/her immune status or have a deviation from the recommended vaccine schedule. Rabies titer testing should be performed after completing vaccine series for the following persons:
- the person is immunosuppressed (has a weakened immune system)
- significant deviations of the vaccine schedule have occurred
- the patient initiated the vaccination series with a questionable quality vaccine internationally
- the person’s titer status is being monitored routinely due to occupational exposure risk to the rabies virus
If the titer result is >0.05 IU/mL, the person is considered immune. If the result is <0.05 IU/mL the level of immunity is inadequate and the person is recommended to have further vaccination and serologic testing.Leave a reply →