Abstract: Objective　To investigate the retesting range of anti-treponema pallidum antibody (TPAb) sample detected by enzyme-linked immunosorbent assay(ELISA).  Methods　A total of 1 257 samples were collected in the first TPAb testing with absorbance (A) value ＞ 0.08 by ELISA. They were retested duplicately by the same reagent kit of same lot number. The samples retested with A vaule ＞ 0.14 were comfirmed by treponema pallidum particale agglutination (TPPA) test.The appropriate retesting range was analyzed statistically. Results　The samples were classified into 7 groups according to the first A value by ELISA: 0.08-0.14，0.15-0.30，0.31-0.60，0.61-0.90，0.91-1.20，1.21-2.00 and ＞2.00. The retesting coincidence rates by ELISA were 16.6%(37/223)，21.6%(56/259)，32.0%(66/206)，50.5%(100/198)，78.0%(99/127)，94.8%(147/155) and 100.0%(89/89). The coincidence rates by TPPA and retesting by ELISA were 0.0%(0/37)，3.6%(2/56)，22.7%(15/66)，38.0%(38/100)，80.8%(80/99)，93.2%(137/147) and 96.6%(86/89). Conclusions　The A value of the retesting range by ELISA is considered appropriate from 0.14-1.20 under a standardized laboratory condition.The appropriate retesting range can assure the accuracy of the testing results and can avoid the waste of manpower and reagents.

Key words: Retesting range, Anti-treponema pallidum antibody, Enzyme-linked immunosorbent assay, Treponema pallidum particale agglutination test