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The Laboratory Evaluation of HIV-Infected Patients


 

Quick Links to Lab Test Information
Suggested Baseline Lab Tests
HIV-Specific Lab Tests
Lab Tests to Evaluate Therapeutic Efficacy
Screening Labs
Other Lab Tests
Resistance Testing
Fever Evaluation

 

 

Suggested Baseline Laboratories
HIV ELISA and Western Blot

Complete Blood Count with differential and platelets

Comprehensive metabolic profile (or, SMA-16)

Urinanalysis

G-6-PD qualitative

Hepatitis B surface antigen

Hepatitis B core antibody

Hepatitis C virus antibody

Hepatitis A virus antibody (optional unless HCV or HBV+)

Syphilis serology

Fasting lipid profile

Cellular immune profile (CD4-lymphocytes) x 2

HIV-1 RNA load by PCR or branched-chain DNA x 2

Chest x-ray EPA + lat

Tuberculin skin test

Toxoplasma gondii IgG antibodies

 

 

Proper Use of HIV-Specific Laboratory Evaluations
HIV Viral Load 1.  Possible acute retroviral syndrome to confirm diagnosis

2.  Newly diagnosed HIV infection to establish baseline and confirm diagnosis

3.  Periodically to follow the course of HIV treatment (see below)

HIV Resistance Assay
(see below)
1.  Prior to initiation of therapy when pre-existing antiretroviral drug resistance is known or suspected - acute or chronic HIV infection.  This recommendation includes most patients in whom antiretroviral therapy is initiated.  Suspect pre-existing antiretroviral drug resistance in the setting of recently acquired infection especially in a metropolitan are.

2.  During antiretroviral therapy after loss of virologic suppression (while on antiretroviral drug therapy)

CD4-Lymphocyte Assay 1.  Prior to initiation of therapy and periodically thereafter to evaluate the indirect effects of virologic suppression and the need for opportunistic infection antimicrobial prophylaxis (see below)

2.  At the time of intercurrent febrile illnesses to evaluate for the possibility of opportunistic infection

 

 

Suggested Laboratories To Evaluate Antiretroviral Therapy
HIV Viral Load 2 & 4 weeks, 2 months, and monthly until undetectable; then do ultrasensitive viral load assay (see below)
Ultrasensitive HIV Viral Load 1-2 months after undetectable on regular sensitivity assay and every 3-6 months thereafter
Complete blood count Monthly x 3-4 months, and then every 2-3 months
Comprehensive metabolic profile Monthly x 3-4 months, and then every 2-3 months
Fasting lipid profile Every 3 months
Serum lactic acid level No routine testing recommended; perform test in correct clinical contest [malaise, nausea, myalgia, anion gap acidosis, NRTI therapy]
Antiretroviral drug levels This may provide information about drug absorption, distribution, metabolism, excretion, and adherence in persons with suboptimal virologic response

 

 

Suggested Routine Screening Laboratories
Hepatitis B surface antibodies After vaccination and annually if nonimmune
Hepatitis B core antibodies Annually if nonimmune
Hepatitis B surface antigen Annually if nonimmune
Hepatitis C virus antibodies Annually if negative at baseline
Syphilis serology Annually, after possible sexual exposure, and/or in the correct clinical context
Urinanalysis Every 6-12 months
Urine screen for STDs Annually and as indicated
Toxoplasma gondii IgG antibodies Periodically/annually if negative at baseline
Tuberculin skin test Annually if nonreactive at baseline or by history

 

 

Other Laboratory Evaluations
Total serum testosterone Males, CD4 <200, chronic opiate use, hypogonadal symptoms, and/or to monitor testosterone replacement therapy (TRT)
Free serum testosterone level If total serum testosterone level is in the range of 200-400
Prostate specific antigen (PSA) Persons of color > age 40 yrs; Caucasians > age 50 yrs; family history of prostate Ca; annually for chronic testosterone replacement therapy
PAP smear Every 6 months
Syphilis serology Annually, after possible sexual exposure, and/or in the correct clinical context
Mammogram Women with average risk at age 40 and every 1-2 years; women at high risk at age 30 and then every 1-2 years
Stool for blood analysis This test may be considered a less sensitive (than colonoscopy) and less invasive yearly exam for persons age >40-50 with a low risk for colon cancer.
Colonscopy or flexible sigmoidoscopy After age 50 for colon cancer screening; schedule of follow-up exams based on risks and findings
Electrocardiogram At baseline and as indicated for persons with one or more risk factors for CAD

 

 

HIV Resistance Testing
Test Timing Information
HIV Genotype On therapy
Usually increasing viral load
Viral load > 1000 copies / cc
Description: Genetic analysis of relevant protease, reverse transcriptase, and possibly other target regions of the HIV genome
Indication:

1. Baseline evaluation prior to therapy in persons at risk for harboring drug-resistant HIV prior to therapy - acutely OR chronically infected (e.g. in persons who may be superinfected with multiple strains of HIV due to unprotected sexual intercourse over a sustained period.)  As it is difficult to accurately assess this type of superinfection via history, across the board resistance testing is probably the best recommendation.

2. Failure or incomplete virologic suppression when therapeutic levels of drugs have been maintained
Cost: 200-400 USD or more

HIV Virtual Phenotype On therapy
Usually increasing viral load
Viral load > 1000 copies / cc
Description: Genetic analysis of relevant protease, reverse transcriptase, and possibly other target regions of the HIV genome compared to database of known drug phenotypes

Indication: same as regular genotype
Cost: 50-100 USD in addition to cost of genotype

HIV Phenotype On therapy
Usually increasing viral load
Viral load > 1000 copies / cc
Description: Measurement of HIV replicative inhibition by relevant concentrations of antiretroviral drugs

Indication: Failure of salvage regimen when genotypic information is not sufficient or too ambiguous
Cost: 300-600 USD or more

 

USD = US dollars

 

 

Suggested Fever Work-up Considerations
CD4
Lymphocyte
Count
Symptoms Recommended Testing
Great than 250 Nonlocalizing Thorough history and physical exam, blood cultures, chest x-ray, CBC, comprehensive metabolic profile, urinanalysis
Headache All of the above plus head imaging (MRI or CT) and lumbar puncture; RPR
Pulmonary Sputum for gram stain, bacterial culture, fungal smear, fungal culture, mycobacterial smear and culture x 3; consider chest CT
Gastrointestinal/diarrhea Stool for leukocytes, bacterial culture, C. difficile; consider colonoscopy and/or EGD
100 - 250 Nonlocalizing Thorough history and physical exam, blood cultures, chest x-ray, CBC, comprehensive metabolic profile, urinanalysis; blood cultures for mycobacteria, tuberculosis skin test, blood cultures for fungus; serum cryptococcal antigen; consider bone marrow biopsy for histopathology and cultures; consider abdominal CT scan
CNS/headache All of the above plus head imaging (MRI or CT) and lumbar puncture; RPR
Pulmonary Sputum for gram stain, bacterial culture, fungal smear, fungal culture, mycobacterial smear and culture x 3; consider chest CT
Gastrointestinal/diarrhea Stool for WBC, bacterial culture, C. difficile; stool for modified acid fast stain; consider abdominal CT; consider colonoscopy and/or EGD
less than 100 Nonlocalizing Thorough history and physical exam, blood cultures, chest x-ray, CBC, comprehensive metabolic profile, urinanalysis; blood cultures for mycobacteria, tuberculosis skin test, blood cultures for fungus; serum cryptococcal antigen; consider bone marrow biopsy for histopathology and cultures; urine for CMV culture; CMV antigen determination on blood; consider abdominal CT scan

 

Quick Menu / Table of Contents
Introduction Principles Management NRTI Info NNRTI Info
PI Info Fusion Inhibitors Coreceptor Inhibitors Integrase Inhibitors Drug Summary
Coformulation Antiretroviral Therapy
Investigational Adherence Lab Evaluation Resistance Tests PEP
Antiretroviral Tables OI Prevention Vaccinations TB Therapy Hepatitis Therapy
OI Diagnosis OI Therapy Bibliography Links Palliative Therapy

 

 

Updated 2/9/2013