| A51 | Early syphilis | NON-BILLABLE CODE |
| A51.0 | Primary genital syphilis | BILLABLE CODE |
| A51.1 | Primary anal syphilis | BILLABLE CODE |
| A51.2 | Primary syphilis of other sites | BILLABLE CODE |
| A51.3 | Secondary syphilis of skin and mucous membranes | NON-BILLABLE CODE |
| A51.31 | Condyloma latum | BILLABLE CODE |
| A51.39 | Other secondary syphilis of skin | BILLABLE CODE |
| A51.4 | Other secondary syphilis | NON-BILLABLE CODE |
| A51.41 | Secondary syphilitic meningitis | BILLABLE CODE |
| A51.42 | Secondary syphilitic female pelvic disease | BILLABLE CODE |
| A51.43 | Secondary syphilitic oculopathy | BILLABLE CODE |
| A51.44 | Secondary syphilitic nephritis | BILLABLE CODE |
| A51.45 | Secondary syphilitic hepatitis | BILLABLE CODE |
| A51.46 | Secondary syphilitic osteopathy | BILLABLE CODE |
| A51.49 | Other secondary syphilitic conditions | BILLABLE CODE |
| A51.5 | Early syphilis, latent | BILLABLE CODE |
| A51.9 | Early syphilis, unspecified | BILLABLE CODE |
