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TPHA TEST KIT

Code: DR0530

Treponema pallidum haemagglutination test (TPHA) for the serodiagnosis of Syphilis.

Introduction
Syphilis is a sexually transmitted disease. The causative organism is Treponema pallidum, a spirochaete which cannot be grown on culture media or in tissue culture. Diagnosis of infection is normally by the detection of antibody specific for Treponema pallidum in the patient’s blood or CSF.
Detection of the antibody becomes possible 3-4 weeks following infection. Detectable levels may remain for long periods after treatment.
Two groups of antibodies are formed in response to infection:
1. Antibodies reactive with non-treponemal antigens (reagin antibodies)
Reagin antibodies are normally found in the active disease. They are detected by the VDRL/Carbon Antigen and RPR tests (Oxoid VDRL Carbon Antigen Test DR0525). Reagin antibodies levels subside after successful treatment¹.
The non-treponemal antibodies may arise for reasons other than syphilitic infection. Positive tests for these should therefore be confirmed by a test for the specific antibodies.
2. Antibodies reactive with the specific antigens of Treponema pallidum:
Specific antibodies persist long after the infection has been successfully treated.
The TPHA test will detect these antibodies. It is a sensitive passive haemagglutination test specifically for the detection of antibodies to Treponema pallidum.

Principle of the test
Tanned fowl erythrocytes are coated with specific antigen and suspended in a diluent ^2,3,4. When diluted positive samples are mixed with the test suspension, antibody to the sensitising antigen causes agglutination of the cells. The cells form a characteristic pattern in the bottom of a microtitration plate well. In the absence of reacting antibody, the cells form a compact button in the well. Uncoated tanned fowl erythrocytes are used as the control cells.

Components of the Kit
DR0531 Test Cell Suspension
2 bottles each containing 8.5 ml of antigen coated formolised tanned fowl erythrocytes. The dropper bottle will dispense 75 ml drops. Each kit contains sufficient suspension for 200 tests.
DR0532 Control Cell Suspension
2 bottles each containing 8.5 ml of uncoated formolised tanned fowl erythrocytes. The dropper bottle will dispense 75 ml drops. Each kit contains sufficient suspension for 200 tests.
DR0533 Diluent Buffer
2 bottles each containing 20ml of buffer.
DR0534 Positive Control Serum
1 bottle containing 2 ml of pre-diluted (1/20) serum, positive for antibodies to Treponema pallidum. The serum should cause agglutination in the screening test and remain positive to a serum dilution of 1/2560 plus or minus one doubling dilution in the quantitative test.
DR0535 Negative Control Serum
1 bottle containing 2 ml of pre-diluted (1/20) serum negative for antibodies to Treponema pallidum.
The human sera used in the manufacture of the controls have been shown to be negative for HBsAG (Hepatitis B surface antigen), Hepatitis C and HIV 1 and 2 antibodies by FDA approved tests.
Instruction Leaflet

Materials required but not provided.
U-well microtitration plate.
Micropipettes and tips to deliver 25 and 100 ml volumes.
Suitable laboratory disinfectant.

Storage
This kit must be stored at 2-8° C. Do not freeze. The kit should not be used after the expiry date printed on the outside of the carton.

Precautions
Reagents contain 0.095% sodium azide as a preservative. Sodium azide is toxic and may react with lead or copper plumbing to produce metal azides which are explosive by contact detonation. To prevent azide accumulation in plumbing flush with copious amounts of water immediately after waste disposal (refer to local environmental reulations).

References
1. Garner M. F., Backhouse J. L., Daskalopoulos G. and Walsh J. L. (1973) J. Clin Path. 26. 258-260.
2. Rathlev T. (1965) W.H.O. VDT/RES/77 65.
3. Rathlev T. (1976) Brit. J. Vener. Dis. 43. 181.
4. Tomizawa T., Kasamatsu S. and Yamaya S.-I. (1969) Jap. J. Med. Sci. Biol. 22. 341-350.
5. Sequeria P. J. L. and Eldridge A. E. (1973) Brit. J. Vener. Dis. 49. 242-248.
6. Cox P. M., Logan L. C. and Norins L. C. (1969) Appl. Microbiol. 18. 485-489.
7. Johnston N. A. (1972). Brit. J. Vener. Dis. 48. 474-478.
8. Uete T., Fukazawa S., Ogi K. and Takeuchi Y. (1971) Brit. J. Vener. Dis. 47. 73-76.
9. Young H., Henrichsen C. and Robertson D. H. H. (1974) Brit. J. Vener. Dis. 50. 341-346.
10. Coffey E. M., Bradford L. L., Naritomi L. S. and Wood R. M. (1972) Appl. Microbiol. 24. 26-30.
11. Dyckman J. D., Storms S. and Huber T. W. (1980) J. Clin. Microbiol. 12. 629-630.