Choosing a TestWhat to consider when choosing what HIV test to use?
Today a number of new HIV testing technologies are available that use less-invasive specimens—such as whole blood from a finger stick or saliva from an oral swab—and that provide rapid results.
Laboratory directors, with input from clinical staff, are responsible for choosing which HIV test will be used in a facility. They will evaluate the performance, quality assurance requirements, and cost of various tests and will evaluate the tradeoffs of using traditional tests or rapid tests as well as performing tests in the laboratory or at the point of care. The following pages offer some general information on HIV tests and direct readers to useful resources to help guide their test selection.
Traditional vs. Rapid HIV TestsAll HIV tests detect the presence of HIV antibodies. The most commonly used HIV tests are EIAs (enzyme immunoassays) and ELISAs (enzyme-linked immunoassays). These traditional HIV tests and the newer rapid tests perform comparably. They have similar accuracy rates, and both have varieties that can test specimens collected by venipuncture or by less-invasive methods, such as oral fluid, urine, and fingerstick blood. Traditional and rapid tests both need to have reactive (positive) test results confirmed with a more specific test, such as a Western Blot.
The major difference between traditional and rapid tests is how quickly their results are available. Rapid HIV tests can produce results in as little as 20 minutes, while traditional tests can take several days. Another feature of rapid tests is that some can be used at the point of care. Immediate results and the flexibility to perform tests at the point of care make rapid tests very useful in emergency departments, where medical encounters are short and the interaction between provider and patient is a one-time occurrence.
Using Rapid HIV TestsFive rapid HIV tests have been licensed for use in the United States:
- OraQuick Rapid HIV-1 and Advance Rapid HIV-1/2 Antibody Tests, manufactured by OraSure Technologies, Inc.
- UniGold Recombigen HIV Test, manufactured by Trinity Biotech
- Reveal G-2 Rapid HIV-1 Antibody Test, manufactured by MedMira, Inc.
- Multispot HIV-1/HIV-2 Rapid Test, manufactured by Bio-Rad Laboratories
- Clearview HIV 1/2 Stat-Pack and Complete 1/2, manufactured by Inverness Medical Innovations
These tests are all interpreted visually on the device itself and require no additional instruments. They differ in terms of what specimens they use and whether or not they have been designated by CLIA as appropriate for point-of-care use. This chart compares the characteristics of the FDA-approved rapid tests.
Test results from rapid HIV tests are interpreted the same as other HIV test results.
- A negative result from a single test is considered negative. However, if the person being tested has been exposed to HIV within the past three months, a repeat test at a later time is recommended because the rapid antibody test may not show a very recent infection.
- A positive (or reactive) result from a rapid HIV test is considered a preliminary positive and must be confirmed by a whole blood or serum-based Western Blot or IFA before the diagnosis of HIV infection is established. If such confirmatory testing yields negative or indeterminate results, follow-up testing should be performed on a blood specimen collected four weeks after the initial reactive rapid HIV test result.
- When internal controls show that an HIV test is invalid, the patient should be offered the option of retesting with another rapid test or submitting a sample for lab-based standard testing and returning for the result or referral to outpatient testing facility.
Considering the CostsRapid tests tend to be more expensive than traditional tests. The current retail price of rapid HIV tests is $14 to $26 per unit. Of course, this price can be significantly lower when tests are purchased in large volumes or through other purchasing arrangements. For example, some health departments have purchased test kits and then redistributed them to testing venues throughout the state or locality, including hospitals. Other programs, such as the federal 340B Drug Pricing Program, make devices and drugs on their formulary available to qualified hospitals at a discounted rate. Products in the 340B Prime Vendor Program are available at even further reduced rates.
In some states, Medicaid is creating new codes for facilities to bill separately for rapid HIV tests. Some private insurers are also evaluating their HIV testing reimbursement policies. As payers devise better reimbursement policies to support routine HIV testing, hospital-based testing can prioritize the use of free or discounted test kits for patients without insurance.
Considering Lab or POC TestsConsidering Laboratory or Point-of-Care Tests
Only 1 in 10 hospitals that use rapid HIV tests use them at the point of care. The major considerations for whether to use lab-based tests or point-of-care tests include:
- Logistics in the ED, such as availability of a small space to properly store, run, and read tests
- Availability of trained staff to perform the test
- Capacity of the laboratory to consistently convey rapid HIV test results quickly
If tests are to be run from the laboratory, the lab will likely require additional staff to handle the high volume (if tests are done routinely) and to ensure timeliness of reading and informing providers of results. If tests are to be performed at the point of care, laboratories will be very concerned with providing oversight and ensuring that all point-of-care requirements are met.
Some tests require serum or plasma specimens and can only be performed in the laboratory (e.g., Reveal and Multispot). Tests that use whole blood (e.g., UniGold, Clearview Complete) or oral fluid (e.g., Oraquick Advance) can be performed easily at the point of care by trained personnel.
What is Required for Point-of-Care Tests?
The Clinical Laboratory Improvement Amendments (CLIA) of 1988 regulates laboratory testing in the United States. The Centers for Medicare and Medicaid Services (CMS) are charged with interpreting CLIA and work closely with the Food and Drug Administration (FDA) and the CDC on their implementation. Some states may have stricter regulations for laboratory testing that make them exempt from CLIA.
CLIA classifies tests according to their complexity. A test may receive a CLIA waiver if it uses direct, unprocessed specimens (such as whole blood or oral fluid) and is easy to perform with little chance of error. Waived tests may be performed outside traditional laboratories by individuals without formal laboratory training. To date, OraQuick ADVANCE, Unigold Recombigen, and Clearview COMPLETE are CLIA-waived; Reveal and Multispot are categorized as moderately complex, which in turn requires that laboratories using those tests adhere to more stringent standards for personnel, quality assurance, and proficiency testing.
Laboratories using waived tests must be registered with the CLIA program. The fee is $150, and it must be renewed every two years. An emergency department can operate as satellite site under another laboratory's CLIA license. Typically, this would be the hospital laboratory's license. Waived laboratories must ensure that all tests performed under their license, including at satellite sites, are used according to manufacturers' instructions and that quality assurance measures are in place (see below).
Click here for more information on registering with CLIA.
Quality AssuranceEffective quality assurance programs minimize the risk of mistakes that can occur in terms of:
- Storage and testing-area temperature
- Test-kit shelf life
- Specimen collection
- Test performance
- Results interpretation
- Confirmatory testing
Hospital laboratory staff are responsible for oversight of quality assurance for any point-of-care testing. They should be involved in developing and maintaining:
- Clear and concise procedures
- Training of personnel
- Verification of competence of personnel
- Proper performance of quality control procedures
- Recognition of when testing does not comply with procedures
For CLIA-waived rapid HIV tests performed at the point of care, nurses or other designated staff can assume responsibility for both collection and testing. Staff must be trained in how to administer the test and provide appropriate quality assurance to ensure that the test continues to be administered pursuant to manufacturer instructions. Hospitals will need to work to develop, implement, and maintain capacity to provide training and quality assurance on an ongoing basis to staff conducting rapid HIV testing. For more information, see Training Staff.
Alternatively, you may decide to send rapid HIV tests to the laboratory. In a laboratory, these duties would be managed by a Quality Control or Quality Assurance (QA) Compliance Officer. In a point-of-care testing setting, it is important to establish a POC coordinator (typically a laboratorian) who is responsible for training, quality control, and quality assurance issues.
The College of American Pathologists Commission on Laboratory Accreditation has developed a comprehensive checklist for point-of-care testing that can inform the implementation of point of care testing. In addition, the CDC maintains comprehensive rapid HIV testing web resources, which include detailed and up-to-date information on CLIA, quality assurance and studies on rapid HIV testing.
Resources
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