Treponema Pallidum Hemagglutination
What is TPHA?
Treponema Pallidum Hemagglutination (TPHA) test is used to detect antibodies in the blood against syphilis, which is a sexually transmitted disease. Syphilis is caused by bacteria, namely, “Treponema pallidum”. It spreads if a person comes in direct contact with a syphilitic lesion (chancre). It has three possible stages which include primary syphilis, secondary syphilis, and late or tertiary syphilis.
Why is TPHA done?
To diagnose Treponema pallidum infection
To screen for sexually transmitted diseases
To monitor the treatment of syphilis
What does TPHA Measure?
Syphilis is a sexually transmitted disease (STD) caused by the bacteria Treponema pallidum. It is most commonly spread by sexual route for example through contact with a syphilitic sore (Chancre). Syphilis is treatable with antibiotics, but it can cause severe health problems if left untreated and can be potentially fatal. It can be transferred from an infected pregnant mother to an unborn child which can lead to serious and potentially fatal consequences for the baby.
There are several stages of syphilis:
· Primary syphilis: Primary stage starts after 2-3 weeks of being infected and usually presents with one or more painless chancres on that part of the body which was exposed to the sexual partner's chancre such as on the penis or vagina. Since it is painless, it may go unnoticed, especially if it is in the rectum or on the cervix. It usually disappears within 4-6 weeks even without any treatment.
· Secondary syphilis: From 6 weeks to 6 months after the chancre first appears, primary syphilis can progress to secondary syphilis if the infected person is left untreated. Its symptom is non-itchy skin rash (rough, red, and spotted) appearing typically on the palms of the hands and the bottoms of the feet. Other symptoms could be fever, fatigue, swollen lymph nodes, sore throat, and body aches.
· Late or tertiary syphilis: If left untreated in previous stages, secondary syphilis can progress to late or tertiary stage in which an infected person may be asymptomatic but continues to have the infection, and this stage can last for years. Complications of tertiary syphilis can occur if still left untreated. The bacteria can damage the heart, eyes, brain, central nervous system (Neurosyphilis), bones, joints, or almost any other part of the body. Tertiary syphilis can last for years and the final stage can lead to mental illness, blindness, other neurological problems, heart disease, and even death.
Interpreting TPHA results
A negative test result means that antibodies against Treponema Pallidum are absent indicating that the patient is not having syphilis infection
A positive test result means that antibodies against Treponema Pallidum are present indicating that the patient is having syphilis infection
However, false positive and false negative test results can also be seen in some cases. All test results should be clinically correlated.
All positive tests should be confirmed with Fluorescent Treponemal Antibodies (FTA-ABS) test.