What laboratory tests are indicated for a patient with a history of Human Immunodeficiency Virus (HIV) presenting with fever?

From the Guidelines

For a patient with HIV presenting with fever, I recommend obtaining a complete blood count (CBC) with differential, comprehensive metabolic panel (CMP), blood cultures (two sets), urinalysis with culture, CD4 count, HIV viral load, and chest X-ray. Additional tests should include C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR) to assess inflammation, and specific tests based on symptoms such as sputum culture for respiratory symptoms, stool studies for gastrointestinal complaints, or lumbar puncture if neurological symptoms are present. Opportunistic infection testing should be considered, including cryptococcal antigen, toxoplasma serology, and tuberculosis testing (QuantiFERON-TB Gold or PPD) 1. The urgency of these tests depends on the patient's clinical status, with more aggressive workup needed for severely immunocompromised patients (CD4 <200 cells/μL) 1. Fever in HIV patients can indicate common infections, opportunistic infections, medication side effects, or HIV-related conditions, making a thorough laboratory evaluation essential for proper diagnosis and treatment. The patient's current antiretroviral therapy adherence and medication list should also be reviewed to identify potential drug fever or immune reconstitution inflammatory syndrome. Some key laboratory tests to consider are:

• CD4 cell count and percentage to assess the patient's immune status 1
• Plasma HIV RNA level (viral load) to monitor the patient's viral load 1
• Complete blood cell count with differential to assess for any blood cell abnormalities 1
• Serum chemistry tests, such as alanine aminotransferase, aspartate aminotransferase, bilirubin levels, to assess liver function 1
• Urinalysis with culture to assess for any urinary tract infections 1
• Cryptococcal antigen test to assess for cryptococcal infection 1
• Toxoplasma serology to assess for toxoplasmosis 1
• Tuberculosis testing (QuantiFERON-TB Gold or PPD) to assess for tuberculosis 1

From the Research

Diagnostic Approach for Fever in HIV Patients

To diagnose the cause of fever in a patient with a history of HIV, the following steps can be taken:

• Identify the clinical symptoms and associated conditions, such as injection drug use, and stage of disease based on the absolute CD4 cell count 2
• Consider the type of infection that may be causing the fever, as opportunistic infections occur only in the presence of severe immunodeficiency 3
• Use a systematic approach to identify the cause of fever, including immune restoration disease, neoplasm, and drug-fever 3

Laboratory Tests for Fever in HIV Patients

The following laboratory tests may be useful in diagnosing the cause of fever in HIV patients:

• CD4 cell count to determine the stage of disease 2, 3
• Complete blood count and blood chemistry tests to identify any underlying infections or conditions 4
• Cultures and sensitivity tests to identify the specific cause of the infection 4

Management of Fever in HIV Patients

The management of fever in HIV patients involves:

• Identifying and treating the underlying cause of the fever 2, 3, 4
• Using antiretroviral therapy to manage HIV infection and prevent opportunistic infections 5, 6
• Educating patients and caregivers about the complexities of fever and its management in HIV patients 5