|
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 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 |
| 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 |
| 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 |
USD = US dollars
| Suggested Fever Work-up Considerations | ||
| CD4 Lymphocyte Count | Symptomatology | 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; CMV PCR (blood); blood culture for mycobacteria; urine histoplasmosis antigen; | |
| <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 |
Updated 1/18/2013