What labs are required prior to initiating Truvada (emtricitabine/tenofovir disoproxil fumarate) therapy?

Required Laboratory Tests for Truvada (Emtricitabine/Tenofovir Disoproxil Fumarate)

Before initiating Truvada (emtricitabine/tenofovir disoproxil fumarate), baseline laboratory testing must include HIV testing, renal function assessment, hepatitis B screening, and STI screening to ensure safe and effective use of the medication. 1

Essential Pre-Initiation Laboratory Tests

HIV Testing

• HIV antibody/antigen combination test (mandatory) 1
• HIV RNA testing if acute HIV infection is suspected 1
• Rationale: Confirms HIV-negative status to prevent resistance development

Renal Function Assessment

• Serum creatinine with calculated creatinine clearance or eGFR 1, 2
• Urinalysis for proteinuria 1
• Rationale: Tenofovir is primarily eliminated by the kidneys and can cause renal impairment

Hepatitis Screening

• Hepatitis B surface antigen (HBsAg) 1
• Hepatitis B surface antibody (HBsAb) 1
• Hepatitis B core antibody (anti-HBc) 1
• Rationale: Discontinuation of Truvada in patients with HBV can cause severe hepatitis flares 2

Additional Recommended Tests

• Complete STI screening (syphilis, gonorrhea, chlamydia) 1
• Pregnancy test for women of childbearing potential 1

Monitoring Laboratory Tests During Truvada Use

Every 3 Months

• HIV testing (to detect breakthrough infections) 1
• STI screening 1

Every 6 Months

• Serum creatinine and calculated creatinine clearance 1
• More frequent monitoring for high-risk patients:
  • Age >50 years
  • Taking medications for hypertension or diabetes
  • Baseline eGFR <90 mL/min 1

Annually

• Hepatitis C antibody test (more frequently for high-risk individuals) 1
• Urinalysis for proteinuria 1

Important Clinical Considerations

• Renal Safety: Truvada is not recommended for patients with creatinine clearance <60 mL/min 1, 2
• Hepatitis B Management: Patients with chronic HBV require careful monitoring after Truvada discontinuation due to risk of severe hepatitis flares 1, 2
• Medication Interactions: Avoid concurrent use with nephrotoxic agents (e.g., high-dose NSAIDs) 2
• Prescription Duration: PrEP prescriptions should not exceed 90 days without interval HIV testing 1

Special Populations Considerations

• Patients with Hepatitis B: Additional liver function monitoring required 1, 2
• Patients with Borderline Renal Function: More frequent renal monitoring recommended 1, 2
• High-Risk Individuals: Consider more frequent STI screening based on risk factors 1

Following these laboratory testing guidelines helps ensure safe and effective use of Truvada while minimizing potential adverse effects on renal function and preventing inappropriate use in HIV-infected individuals.