Required Lab Tests Before Starting Kevzara
Kevzara (sarilumab) requires baseline lab tests to assess infection risk, liver function, blood counts, and lipid levels before the first dose. These follow FDA labeling and rheumatoid arthritis treatment guidelines.[1]
- Tuberculosis (TB) screening: Test for latent TB with a tuberculin skin test, interferon-gamma release assay (e.g., QuantiFERON-TB Gold), or chest X-ray if indicated. Treat active or latent TB before starting.
- Blood counts: Complete blood count (CBC) with differential and absolute neutrophil count (ANC). Avoid starting if ANC < 2000/mm³, platelets < 150,000/mm³, or hemoglobin < 8.5 g/dL (adjusted for chronic disease).
- Liver enzymes: Alanine aminotransferase (ALT) or aspartate aminotransferase (AST). Do not initiate if ALT/AST > 1.5 times upper limit of normal (ULN).
- Lipids: Fasting lipid profile (cholesterol, LDL, HDL, triglycerides), as Kevzara raises these levels.
Retest these labs 4-8 weeks after starting, then every 3 months. Discontinue if ANC drops below 500/mm³, platelets < 50,000/mm³, or ALT/AST > 5x ULN.[1]
Why These Tests Matter for Kevzara
Kevzara, an IL-6 receptor blocker, increases infection risk (including serious ones like TB), neutropenia, thrombocytopenia, elevated liver enzymes, and hyperlipidemia. Baseline tests identify at-risk patients; untreated issues can lead to hospitalization or treatment halt.[1][2]
Tests for Patients with Hepatitis or Extra Risks
- Hepatitis B/C: Screen high-risk patients (e.g., IV drug users) with HBsAg, anti-HBc, and anti-HCV. Monitor carriers closely; reactivation risk exists.
- Vaccinations: Update live vaccines (e.g., MMR, varicella) before starting, as Kevzara impairs immune response post-initiation.[1]
How Often to Monitor After Starting
| Time Point | Tests |
|------------|-------|
| Baseline | TB screen, CBC/ANC/platelets, LFTs (ALT/AST), lipids |
| 4-8 weeks | CBC/ANC/platelets, LFTs |
| Every 3 months | Same as above; annual lipids |
| As needed | TB screen if exposure suspected |
Dose adjustments apply for moderate ANC (500-1000/mm³) or elevated LFTs.[1]
Kevzara vs. Other IL-6 Inhibitors (e.g., Olumiant, Xeljanz)
Kevzara shares similar pre-treatment labs with baricitinib (Olumiant) and tofacitinib (Xeljanz)—TB screen, CBC, LFTs—but mandates lipids upfront, unlike some JAK inhibitors. All carry black-box warnings for infections, clots, and malignancy.[1][3]
[1]: Kevzara Prescribing Information (Sanofi/Regeneron)
[2]: FDA Label for Kevzara
[3]: Arthritis Foundation Guidelines on Biologics