FeLV & FIV Testing Strategy: Retrovirus Screening in Cats¶
FeLV and FIV are the two clinically significant feline retroviruses, but their testing strategies differ fundamentally: FeLV is antigen-detected; FIV is antibody-detected. This distinction drives everything about interpretation.
The Antigen/Antibody Distinction¶
| Virus | Test target | Rationale |
|---|---|---|
| FeLV | p27 antigen | Detects active viral replication (persistent infection) |
| FIV | Antibody | Virus persists at low load; antibody is the reliable marker |
When to Screen¶
| Scenario | Action |
|---|---|
| New cat / kitten intake | Screen both (standard of care) |
| Sick cat (anemia, lymphoma, stomatitis, immunosuppression) | Screen both |
| Pre-vaccination | Establish status |
| Multi-cat household / breeding | Screen all |
Interpretation¶
FeLV (p27 antigen)¶
| Result | Interpretation |
|---|---|
| Positive | Active infection — confirm (retest 6–12 wks or PCR) |
| Negative | No active infection detected |
FIV (antibody)¶
| Result | Interpretation |
|---|---|
| Positive (adult) | Consistent with FIV infection |
| Positive (kitten < 6 mo) | May be maternal antibody — retest after 6 months |
| Negative | No infection detected |
The Confirmation Principle¶
A single positive — especially FeLV — must be confirmed before irreversible decisions (euthanasia, rehoming):
- FeLV: retest in 6–12 weeks (persistent stays positive) or PCR (proviral DNA).
- FIV kitten: retest after 6 months (maternal antibody wanes).
References¶
- Giselbrecht J, Jähne S, et al. Evaluation of a Revised Point-of-Care Test for the Detection of Feline Leukaemia p27 Antigen and Anti-p15E Antibodies in Cats. Viruses. 2024;16(4):553. PMID: 38675954
- Laska-Modzelewska A, Pawelczak P, et al. Comparative evaluation of nine lateral flow assays for FIV antibody detection using an in-house ELISA as a reference method. BMC Vet Res. 2026. PMID: 41572271
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Authored by: Migibio Clinical & Scientific Affairs, Guangzhou Magic Biotech Co., Ltd.
Reviewed by: Migibio R&D Quality Committee
Last updated: 2026-08-13
Disclosure: Migibio (Guangzhou Magic Biotech Co., Ltd.) is the manufacturer of the FIA680/FIA880 analyzers and FICT reagents referenced in this content. See our Editorial & Review Policy.
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