| Test name | Alternative name for |
|---|
| JAK2 | MH JAK2 V617F |
| JAK2 V617F | MH JAK2 V617F |
| Japanese B Encephalitis Serology | |
| Japanese encephalitis virus PCR | |
| JBE PCR | Japanese encephalitis virus PCR |
| JC Virus Antibodies | |
| JC virus PCR | Polyomavirus PCR (includes BK and JC viruses) |
| Jo-1 | ENA |