Pre-Biologic Workup for Rituximab
Before initiating rituximab, you must screen for hepatitis B virus infection (HBsAg and anti-HBc), hepatitis C virus infection, latent tuberculosis, obtain a complete blood count with differential, and measure baseline immunoglobulin levels (IgG, IgA, IgM). 1, 2
Mandatory Infectious Disease Screening
Hepatitis B Virus (Critical Priority)
- Screen all patients with both HBsAg and anti-HBc before initiating rituximab 2
- Rituximab carries a high risk of hepatitis B reactivation, classified as a high-risk immunosuppressive agent 3
- For patients who are HBsAg-positive OR anti-HBc positive (regardless of HBsAg status): initiate prophylactic antiviral therapy (entecavir or tenofovir) rather than monitoring alone 3, 4
- Start antiviral prophylaxis 2-4 weeks before rituximab initiation 3
- Continue antiviral prophylaxis for 12 months after the last rituximab dose (not just 6 months as with other immunosuppressants), as HBV reactivation can occur up to 1-2 years after rituximab discontinuation 3
Hepatitis C Virus
Latent Tuberculosis
Baseline Laboratory Testing
Complete Blood Count
- Obtain CBC with differential and platelet count prior to the first dose 2
- This establishes baseline values for monitoring cytopenias, which are a known toxicity of rituximab 1
Immunoglobulin Levels
- Measure baseline serum IgG, IgA, and IgM levels before starting rituximab 4, 5, 6
- Pre-existing hypogammaglobulinemia (IgG <6 g/L) predicts increased risk of developing severe hypogammaglobulinemia and serious infections after rituximab 4, 5
- Baseline IgG levels correlate with post-rituximab hypogammaglobulinemia risk 4
- This is particularly important as hypogammaglobulinemia can persist long-term and may require immunoglobulin replacement therapy 5, 7
Vaccination Strategy
Timing Considerations
- Administer all indicated vaccines BEFORE starting rituximab whenever possible 8
- Vaccine responses are severely impaired for 1-6 months after rituximab, with humoral responses to influenza and pneumococcal vaccines particularly affected 8
- If patients are already on rituximab, vaccines should be given at least 6 months after the start but 4 weeks before the next course 8
Priority Vaccinations to Check/Administer
- Pneumococcal vaccine (PCV followed by PPSV23) 8
- Influenza vaccine (annual) 8
- Hepatitis B vaccine (if non-immune) 8
- Tetanus toxoid 8
- Haemophilus influenzae b 8
- Hepatitis A 8
- Neisseria meningitides 8
- Rubella (for women of childbearing age) 8
Live Vaccines
- Herpes zoster vaccination may be considered, but only in less severely immunosuppressed patients and only if varicella zoster antibody positive 8
- Live vaccines should generally be withheld once rituximab is started 9
Additional Screening Considerations
Cardiovascular Assessment
- Patients with clinically significant cardiovascular disease require special consideration for infusion protocols 2
Pregnancy Status
- Screen for pregnancy before initiating rituximab 6
Hypersensitivity History
- Screen for hypersensitivity to murine proteins 6
Congestive Heart Failure
- Assess for presence of congestive heart failure 6
Common Pitfalls to Avoid
- Do not rely on HBsAg alone for hepatitis B screening—you must also check anti-HBc, as patients with resolved HBV infection (HBsAg-negative/anti-HBc positive) remain at risk for reactivation with rituximab 3
- Do not delay vaccination until after rituximab is started—vaccine responses will be severely impaired for months after B-cell depletion 8
- Do not skip baseline immunoglobulin measurements—pre-existing hypogammaglobulinemia significantly increases infection risk and may require closer monitoring or immunoglobulin replacement 4, 5
- Do not use standard 6-month antiviral prophylaxis duration—rituximab requires 12 months (potentially up to 24 months) of prophylaxis due to prolonged B-cell depletion 3