Human T-Cell Lymphotropic Virus Types I and II (HTLV-I/-II) Antibody Confirmation, Serum
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Confirmatory detection of human T-cell lymphotropic virus types I and II (HTLV-I and HTLV-II)-specific IgG antibodies in human serum specimens that are consistently reactive by initial screening tests
Differentiating between HTLV-I- and HTLV-II-specific IgG antibodies
This confirmatory assay should be ordered only on specimens that are consistently reactive by anti-HTLV-I/-II screening assays (see HTLVI/9539 Human T-Cell Lymphotropic Virus Types I and II [HTLV-I/-II] Antibody Screen with Confirmation, Serum).
Line Immunoassay (LIA)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
HTLV-I/-II Ab Confirmation, S
HTLV I/II Confirmation
HTLV I/II Line Immunoassay
HTLV I/II Confirmation
HTLV I/II Line Immunoassay
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Collection Container/Tube: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Mild OK; Gross OK
Mild OK; Gross OK
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
|Serum SST||Frozen (preferred)|
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Human T-cell lymphotropic virus types I and II (HTLV-I and HTLV-II) are closely related exogenous human retroviruses. HTLV-I was first isolated in 1980 from a patient with a cutaneous T-cell lymphoma, while HTLV-II was identified from a patient with hairy cell leukemia in 1982.
HTLV-I infection is endemic in southwestern Japan, Caribbean basin, Melanesia, and parts of Africa, where HTLV-I seroprevalence rates are as high as 15% in the general population. In the United States, the combined HTLV-I and HTLV-II seroprevalence rate is about 0.016% among voluntary blood donors. About half of these infected blood donors are infected with HTLV-I, with most of them reporting a history of birth in HTLV-I-endemic countries or sexual contact with persons from the Caribbean or Japan. Smaller percentages report a history of either injection drug use or blood transfusion. Transmission of HTLV-I occurs from mother to fetus, sexual contact, blood transfusion, and sharing of contaminated needles. Two diseases are known to be caused by HTLV-I infection: adult T-cell leukemia or lymphoma (ATL), and a chronic degenerative neurologic disease known as HTLV-I-associated myelopathy (HAM) or tropical spastic paraparesis (TSP). Cases of polymyositis, chronic arthropathy, panbronchiolitis, and uveitis also have been reported in HTLV-I-infected patients.
HTLV-II is prevalent among injection drug users in the United States and in Europe, and >80% of HTLV infections in drug users in the United States are due to HTLV-II. HTLV-II also appears to be endemic in Native American populations, including the Guaymi Indians in Panama and Native Americans in Florida and New Mexico. HTLV-II-infected blood donors most often report either a history of injection drug use or a history of sexual contact with an injection drug user. A smaller percentage of infected individuals report a history of blood transfusion. HTLV-II is transmitted similarly to HTLV-I, but much less is known about the specific modes and efficiency of transmission of HTLV-II. The virus can be transmitted by transfusion of cellular blood products (whole blood, red blood cells, and platelets). HTLV-II infection has been associated with hairy-cell leukemia, but definitive evidence is lacking on a viral etiologic role. HTLV-II has also been linked with neurodegenerative disorders characterized by spastic paraparesis and variable degrees of ataxia.
Infection by these viruses results in the appearance of specific antibodies against the viruses that can be detected by serologic tests such as EIA. For accurate diagnosis of HTLV-I or HTLV-II infection, all initially screening test-reactive results should be verified by a confirmatory test, such as Western blot or line immunoassay.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
This confirmatory assay should be ordered only on specimens that are reactive by an anti-HTLV-I/-II screening immunoassay.
Negative confirmatory test results indicate the absence of both human T-cell lymphotropic virus types I and II (HTLV-I and HTLV-II)-specific IgG antibodies in serum.
A reactive screening (EIA) result with a negative or indeterminate confirmatory (line immunoassay) test result suggests either a false-reactive screening test result or a seroconverting HTLV infection. Repeat testing in 1 to 2 months can clarify the final infection status. Persistently indeterminate confirmatory test results indicate absence of HTLV infection.
Positive results for HTLV-I antibodies indicate the confirmed presence of HTLV-I IgG antibodies in serum, based on 2 visible antibody bands that include gp21-I/-II band, or 3 or more bands, and the sum of the
gp46-I and p19-I band intensity is greater than the gp46-II band intensity.
Positive results for HTLV-II antibodies indicate the confirmed presence of HTLV-II IgG antibodies in serum, based on 2 visible antibody bands that include gp21-I/-II band, or 3 or more bands, and the gp46-II band intensity is a) greater than the gp46-I band intensity and b) > or =the sum of the gp46-I and p19-I band intensity.
Indeterminate results indicate the presence of gp21-I/-II band only or combination of any 2 bands without a detectable gp21-I/-II band. Patients with indeterminate test results with known risk factors for HTLV-I or HTLV-II infection should undergo repeat confirmatory antibody testing in 1 to 2 months to determine final infection status.
Differentiation of HTLV-I and HTLV-II infection is not possible (ie, nontypeable HTLV antibodies) when the band intensity pattern does not meet the criteria of positive HTLV-I or HTLV-II antibody band intensity pattern.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
A negative line immunoassay result does not preclude the possibility of exposure to human T-Cell lymphotropic virus types I and II.
Results from this confirmatory assay should always be interpreted together with the reactive screening test result on a given specimen.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Zrein M, Louwagie J, Boeykens, et al: Assessment of a new immunoassay for serological confirmation and discrimination of human T-cell lymphotropic virus infections. Clin Diagn Lab Immunol 1998;5:45-49
2. Sabino EC, Zrein M, Taborda CP, et al: Evaluation of the INNO-LIA HTLV I/II assay for the confirmation of human T-cell leukemia virus-reactive sera in blood bank donations. J Clin Microbiol 1999;37:1324-1328
3. Murphy E, Roucoux D: The epidemiology and disease outcome of human T-lymphotropic virus type II. AIDS Rev 2004;6:144-154
4. Projetti FA, Carneiro-Projetti AB, Catalan-Soares BC, et al: Global epidemiology of HTLV-I infection and associated diseases. Oncogene 2005;24:6058-6068
Method Description Describes how the test is performed and provides a method-specific reference
INNO-LIA HTLV I/II is a line immunoassay that uses well defined antigens derived from man T-cell lymphotropic virus types I and II (HTLV-I and HTLV-II) immunodominant proteins. The antigens used are either recombinant proteins or synthetic peptides, highly purified and fixed on a nylon membrane strip. The sequences are selected to allow the detection of antibodies with a wide specificity to all known isolates of the HTLV strains. The antigenicity exhibited by these proteins and peptides is either common to both HTLV-I and HTLV-II, or type-specific to 1 of the 2 viruses to allow confirmation and discrimination in a single assay. Two gag (p19-I/II, p24-I/II) and 2 env (gp46-I/II, gp21-I/II) bands are applied as nontype-specific antigens, which are used to confirm the presence of antibodies against HTLV-I/II. The type-specific antigens for HTLV-I (gag p19-I, env gp46-I) and for HTLV-II (env gp46-II) are applied to differentiate between HTLV-I and HTLV-II infections. In addition, 4 control lines are coated: 1 negative control (streptavidin), and 3 positive control lines, a strong (antihuman IgG), a moderate (human IgG), and a weak (human IgG) line.
This assay is based on the enzyme immunoassay principle. Specific anti-HTLV antibodies, if present in the clinical sample, will bind to the HTLV antigen lines on the strip. Subsequently, goat antihuman IgG antibodies labeled with alkaline phosphatase are added and will bind to any HTLV antigen-antibody complex previously formed. Incubation with a chromogenic substrate produces a dark brown color in proportion to the amount of specific antibodies present in the sample. The color development is stopped with sulfuric acid. If the sample contains no HTLV-specific antibodies, only a low background color develops.
Every sample is classified as negative, indeterminate, or positive, then further classified as HTLV-I, HTLV-II, or untypeable-positive according to the antibody band reactivity. (INNO-LIA HTLV I/II Score kit package insert 25957 v5; INNOGENETICS N.V., Gent, Belgium)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Wednesday; 3 p.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Stored serum 7 days
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
This test uses a reagent or kit labeled by the manufacturer as Research Use Only. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
|Result ID||Reporting Name||LOINC Code|
|83277||HTLV-I/-II Ab Confirmation, S||22362-8|
|23898||HTLV-I/-II Bands||In Process|
|23899||HTLV-I/-II Discrimination||In Process|