Initial Laboratory Evaluations and Treatment Recommendations for HIV Patients
All individuals diagnosed with HIV should undergo a comprehensive initial laboratory evaluation including CD4 cell count, HIV viral load, HIV resistance testing, and screening for coinfections before initiating antiretroviral therapy, which should be started in all HIV-positive individuals regardless of CD4 count. 1
Initial Laboratory Evaluation
HIV-Disease Tests
- HIV confirmation: Serologic testing to confirm HIV status if previously tested anonymously or without documentation 1
- CD4 cell count and percentage: Essential for determining disease stage and immunosuppression level 1
- Plasma HIV RNA level (viral load): Establishes baseline for monitoring treatment response 1
- HIV resistance testing: Genotypic testing for all patients to detect transmitted drug resistance 1
- InSTI resistance testing not routinely recommended unless suspected exposure to InSTI-resistant virus 1
Safety Laboratory Tests
- Complete blood count with differential 1
- Chemistry profile: 1
- Liver function (ALT, AST, bilirubin, albumin, alkaline phosphatase)
- Kidney function (electrolytes, BUN, creatinine)
- Fasting blood glucose
- Fasting lipid profile
- Urinalysis for protein and glucose 1
- HLA B*5701 testing before prescribing abacavir 1
- G6PD screening in appropriate racial/ethnic groups 1
Coinfection and Comorbidity Screening
- Viral hepatitis screening: 1
- Hepatitis B (surface antigen, surface antibody, core antibody)
- Hepatitis C antibody
- Hepatitis A total antibody
- Tuberculosis screening (tuberculin skin test or interferon-gamma release assay) 1
- STI screening: 1
- Syphilis serology (VDRL/RPR)
- Gonorrhea and chlamydia testing at all exposed sites
- Toxoplasma gondii IgG serology 1
- Cytology: Cervical Pap test; consider anal Pap test if indicated 1
- CMV and herpesvirus screening in appropriate patients 1
- Chest radiography for patients with positive TB tests or underlying lung disease 1
Treatment Recommendations
When to Start Antiretroviral Therapy
- Initiate ART in all HIV-infected individuals regardless of CD4 count 1
- Immediate ART initiation is particularly urgent for: 1
- Symptomatic HIV disease
- CD4 count <200 cells/μL
- Pregnancy
- AIDS-defining conditions
- Acute/early HIV infection
Initial Regimen Selection
- Preferred regimens typically include:
- An integrase strand transfer inhibitor (InSTI) plus two nucleoside reverse transcriptase inhibitors (NRTIs) 1
- Regimen selection should consider:
- Resistance testing results
- Potential drug interactions
- Comorbidities (renal/liver disease, cardiovascular risk)
- Pregnancy status or potential
Follow-up Monitoring
- 4-6 weeks after starting ART: 1
- Assess adherence and medication tolerability
- Measure HIV RNA level
- If HIV RNA not declining appropriately by 4-6 weeks: Perform resistance testing 1
- Continue monitoring until viral suppression, then every 3-6 months 1
Common Pitfalls and Caveats
- Do not delay ART initiation while waiting for all laboratory results unless there is concern for cryptococcal meningitis or TB meningitis 1
- CD8 cell count and CD4:CD8 ratio should not be used for clinical decision-making 1
- Viral load may be transiently increased by vaccinations and intercurrent illnesses 1
- Discordance between CD4 count and viral load trends occurs in approximately 20% of patients and may complicate treatment decisions 1
- Use the same viral load assay throughout patient care to ensure consistent monitoring 1
- B symptoms (fever, night sweats, weight loss) should prompt thorough evaluation even if CD4 counts are stable 2
By following this comprehensive initial evaluation and prompt treatment initiation approach, clinicians can significantly reduce HIV-related morbidity and mortality while improving long-term quality of life for people living with HIV.