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    Laboratory Services Section
    MC 1947
    PO Box 149347 Austin, TX 78714-9347
    1100 W. 49th Street
    Austin, TX 78756-3199

    Phone: (512) 776-7318
    Fax: (512) 776-7294

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Serological Analysis Group Tests

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The Serological Analysis Group aids submitters in the diagnosis of many diseases by detecting antibodies to those diseases. The following table lists the tests performed by the Diagnostic Serology and HIV/STD Teams. There are links to descriptions of the diseases, as well as links to descriptions of the assays used.

Note: External links to other sites are intended to be informational and do not have the endorsement of the Texas Department of State Health Services. These sites may also not be accessible to people with disabilities.

 

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

Serology Tests

- A -^ Top

Test

Type of Assay

Expected/Significant Results

Frequency of Testing

Adenovirus Complement Fixation (CF) A 4 fold or greater rise in titer between acute and convalescent sera is evidence of infection with adenovirus. Weekly
Amebiasis Enzyme Immunoassay (EIA)   Not available at TDSHS
Aspergillus Immunodiffusion (ID) 1 or 2 bands are present in any clinical phase; three or more bands indicate invasive disease. Weekly

- B -^ Top

Test

Type of Assay

Expected/Significant Results

Frequency of Testing

Blastomycosis Complement Fixation (CF)

Immunodiffusion (ID)

CF titer parallels severity. Titers of 1:8 or greater is considered presumptive evidence for Blastomycosis. Negative CF reaction does not exclude the existence of B. dermatitidis infection. Cross-reactions occur frequently with Coccidioidomycosis and Histoplasmosis. A precipitin band in the Immunodiffusion test denotes recent or current infection. Weekly
Brucellosis Agglutination A single titer >= 1:160 is evidence of a prior infection, but does not confirm that it was recent. The most convincing evidence of recent infection is a 4 fold rise in titer between an acute and convalescent serum. Weekly

- C -^ Top

Test

Type of Assay

Expected/Significant Results

Frequency of Testing

Coccidioidomycosis Complement Fixation (CF)

Immunodiffusion (ID)

CF titer parallels severity. A titer of 1:32 indicates disseminating disease. A negative CF reaction does not exclude a diagnosis of coccidioidomycosis. A positive CF titer and the presence of a precipitin band denotes recent or current infection. Weekly
Cryptococcus Agglutination   Not available at TDSHS
Cytomegalovirus (CMV) Enzyme Immunoassay (EIA) A significant rise in titer between paired sera may indicate a recent primary infection or reactivation of a latent infection. However, virus isolation should be attempted. If the initial serum is negative, and the 2nd serum is positive, a diagnosis of primary infection can be made. Persistently high titers in infants with typical symptoms may indicate congenital infection. Weekly

- D -^ Top

Test

Type of Assay

Expected/Significant Results

Frequency of Testing

Dengue Fever Enzyme Immunoassay (EIA) A 4 fold change in antibody titer or the presence of Dengue-specific IgM in CSF confirms a recent infection. Reactive IgM result in a single serum sample is considered only presumptive evidence of recent infection, because the IgM can be detected for months and up to a year after Dengue infection. Serological cross-reactions with other flaviviruses (SLE  and WN) preclude definitive diagnosis without confirmation by serum neutralization from the CDC. Weekly

- E -^ Top

Test

Type of Assay

Expected/Significant Results

Frequency of Testing

Eastern Equine Encephalitis (EEE) Enzyme Immunoassay (EIA) A 4 fold titer increase on paired sera is required for best evidence of current infection. Cross-reactions occur with Western Equine Encephalitis. Weekly
Ehrlichia Immunofluoresence (IFA) A 4 fold or greater rise in titer between acute and convalescent sera, collected four weeks apart, is evidence for infection with Ehrlichia. Twice weekly

- H -^ Top

Test

Type of Assay

Expected/Significant Results

Frequency of Testing

Hantavirus Enzyme Immunoassay (EIA) A 4 fold rise in IgG antibody titer or the presence of IgM in acute-phase sera is diagnostic for hantaviral disease. Weekly
Hepatitis A Antibody Enzyme Immunoassay (EIA) Measures the total antibodies to HAV (IgG, IgM and IgA) and is positive in acute hepatitis A and remains positive indefinitely. The total antibody test to HAV is used to determine previous exposure to HAV and assess immune status. As needed
Hepatitis A IgM Enzyme Immunoassay (EIA) A positive test is indicative of recent infection with HAV. As needed
Hepatitis B core Antibody Enzyme Immunoassay (EIA) In the absence of HBsAg and antibody to HBsAg, a positive anti-HBc is a serological marker of recent infection. In the presence of antibody to HbsAg, a positive anti-HBc is a serological marker of past exposure. Twice weekly
Hepatitis B e Antibody Enzyme Immunoassay (EIA) A positive anti-HBe sera indicates a reduced level of infectious virus and seroconversion in Hepatitis B carriers. Anti-HBe positivity in the Hepatitis B carriers is often associated with chronic asymptomatic infection. Not available at TDSHS

- H -^ Top

Test

Type of Assay

Expected/Significant Results

Frequency of Testing

Hepatitis B e Antigen Enzyme Immunoassay (EIA) HbeAg is found in the early phase of the hepatitis B infection and is associated with increased risk of transmitting the virus to their contacts. Persistence of HbeAg in the hepatitis B carrier is often associated with chronic active hepatitis. Not available at TDSHS
Hepatitis B surface Antibody Enzyme Immunoassay (EIA) Antibody to HBsAg with or without anti-HBc, specifies immunity against reinfection. Antibody to HBsAg without anti-HBc develops in persons who receive hepatitis B vaccine. Twice weekly
Hepatitis B surface Antigen Enzyme Immunoassay (EIA) Repeatedly high reactive sera are not confirmed by a confirmatory test at TDSHS Laboratory. Low reactive results are further tested for the presence of HepBcore antibodies. Daily
Hepatitis C Antibody Enzyme Immunoassay (EIA) Sera positive for HCV by EIA method should be confirmed by additional supplementary test. Three times weekly
Histoplasmosis Complement Fixation (CF)

Immunodiffusion (ID)

CF titers parallel severity. Yeast-phase and mycelial-phase antigens are used. Cross-reactions are frequent with Blastomycosis and Coccidioidomycosis. Skin test affects antibody levels significantly. Demonstration of both an H and an M band is presumptive evidence for active disease. The M band may appear alone in either acute or chronic disease. The H band is found in active disease but is most affected by the skin test. Weekly

- H -^ Top

Test

Type of Assay

Expected/Significant Results

Frequency of Testing

Human Immunodeficiency Virus (HIV)


Enzyme Immunoassay (EIA) The HIV COMBO procedure for serum (enzyme immunoassay) includes testing for HIV-2, HIV-2 and the p24 antigen. All HIV reactive specimens on serum are confirmed with the HIV Multispot. Oral Fluid and DBS specimens are tested for HIV-1 and confirmation is by Western Blot. Specimens that are found to be repeatedly reactive on the EIA must be confirmed using a more specific test – the Multispot for serum or the Western Blot for oral fluid or DBS.
Daily
Western Blot (WB) The Western Blot also detects antibodies to HIV-1 present in human serum, oral fluid or DBS.  If antibodies to any of the major HIV antigens are present in the specimen in sufficient concentration, bands corresponding to the position of one or more of the following HIV proteins (p) or glycoproteins (gp) will be seen on the nitrocellulose strip:  p17, p24, p31, gp41, p51, p55, p66, gp120, gp160 (the number refers to apparent molecular weight in kilodaltons). Interpretation is based on the presence or absence of these bands. A sample that is repeatedly reactive in the EIA and reactive in the Western Blot is presumed to be reactive for antibodies to HIV-1. Individuals with reactive tests should be referred for medical evaluation. A diagnosis of AIDS can only be made if an individual meets the case definition established by the CDC. Twice weekly
Multispot Qualitative Immunoassay The Multispot is a rapid test to detect and differentiate circulating antibodies to Human Immunodeficiency Virus Types I and 2 (HIV-1, HIV-2). This test is suitable for use in multi-test algorithms designed for statistical validation of an HIV screening test result or as part of an HIV-1/HIV-2 diagnostic testing algorithm that includes differentiation of HIV-1 and HIV-2 antibodies.  Daily

- L -^ Top

Test

Type of Assay

Expected/Significant Results

Frequency of Testing

Legionnaire's Disease Immunofluoresence (IFA) A four-fold or greater rise in titer to 128 from acute-phase to convalescent-phase of illness is considered positive in a patient with pneumonia. Twice weekly
Lyme Disease Enzyme Immunoassay (EIA) Lyme Disease results should serve as an aid to diagnosis and should be interpreted in relation to patient’s clinical picture and other epidemiological data. Sera from patients with other spirochetal diseases (including syphilis) and other conditions may have antibodies which cross-react with B. burgdorferi antigens. Some serum samples, especially those from early Lyme disease and those receiving antibiotic therapy early after EM, may not contain detectable levels of antibodies. Twice weekly

- M -^ Top

Test

Type of Assay

Expected/Significant Results

Frequency of Testing

Measles
Enzyme Immunoassay (EIA) Measles specific IgM in a single sera or a four-fold or greater rise in titer between acute and convalescent phase sera taken at 7-14 day interval is the basis of diagnosis of acute infection. The presence of measles specific IgG antibody in a single serum indicates past infection or vaccination. Twice weekly
Mumps
Enzyme Immunoassay (EIA)

Immunofluoresence (IFA)

Mumps specific IgM in a single sera by IFA or a four-fold or greater rise between acute and convalescent phase sera by EIA is presumptive evidence for infection with mumps virus. Cross-reactivity between mumps and parainfluenza virus exists, therefore, simultaneous testing for parainfluenza virus is recommended in atypical mumps cases. Weekly

- P -^ Top

Test

Type of Assay

Expected/Significant Results

Frequency of Testing

Plague Hemagglutination A titer of >1:10, in the absence of known recent plague-vaccine history or exposure is a presumptive diagnosis for plague. A single serum titer of >1:128 in the absence of vaccination, or a 4 fold rise in titer between paired sera, collected more than 2 weeks apart, is considered positive for a recent infection and must be reported to health authorities. Weekly

- Q -^ Top

Test

Type of Assay

Expected/Significant Results

Frequency of Testing

Q Fever Immunofluoresence (IFA) A 4 fold or greater rise in titer between acute and convalescent phase sera is evidence for recent infection. In acute Q-fever infections, antibodies to the phase II antigen are usually higher than the antibody titer to phase I. In chronic Q fever infection, however, phase I titers eventually equal or exceed phase II titers. A single Q fever IFA titer >= 1:256 is evidence of a prior infection, but, it does not confirm that the infection was recent. Weekly

- R -^ Top

Test

Type of Assay

Expected/Significant Results

Frequency of Testing

Rocky Mountain Spotted Fever Immunofluoresence (FI) A 4 fold or greater rise in titer between acute and convalescent phase sera is convincing serological evidence of recent rickettsial infection. Twice weekly
Rubella IgG
Enzyme Immunoassay (EIA) A 4 fold or greater rise in antibody titer between paired acute and convalescent phase sera is confirmation of clinical rubella infection. The presence of rubella specific IgG antibody in a single serum specimen indicates prior infection and possibly immunity if the rubella specific IgG antibody titer is >=10 mIU/ml of serum. Daily
Rubella IgM
Enzyme Immunoassay (EIA) Presence of rubella-specific IgM antibodies is confirmation of clinical rubella infection. Twice weekly

- S-^ Top

Test

Type of Assay

Expected/Significant Results

Frequency of Testing

St Louis Encephalitis (SLE) Enzyme Immunoassay (EIA) A four-fold change in antibody titer or the presence of SLE-specific IgM in CSF confirms a recent infection. Reactive IgM result in a single serum sample is considered only presumptive evidence of recent infection, because the IgM can be detected for months and up to a year after SLE infection. Serological cross-reactions with other flaviviruses (WN and Dengue Fever) preclude definitive diagnosis without confirmation by serum neutralization from the CDC. Weekly
Syphilis (Screen)
Multiplex Flow Immunoassay
Specimens tested for syphilis follow a reverse algorithm for diagnosis. If the specimen is reactive for Syphilis IgG it indicates a past or current infection with Syphilis. Confirmation is performed with the RPR (Rapid Plasma Reagin) Card and TP-PA (Treponema pallidum Particle Agglutination) test. The RPR is non-specific for syphilis and the TP-PA is specific for Treponema pallidum. Diagnosis is dependent on the interpretation of these three assay results. Daily
Syphilis (Confirmation, RPR) Rapid Plasma Reagin (RPR) Card This is a confirmatory test for syphilis. A reactive test may indicate past or present infection with a pathogenic treponeme. A four-fold rise in titer on a repeat specimen may indicate an infection, a reinfection or a treatment failure. A four-fold decrease in titer in early syphilis usually indicates adequate syphilis therapy. False positive reactions can result from serum antibodies unrelated to syphilis infection; therefore, a reactive result should be confirmed by confirmatory treponemal tests. A nonreactive RPR card test and no clinical evidence of syphilis may indicate no current infection or an effectively treated infection, however, false negative results can be observed during primary syphilis, in secondary syphilis as a result of prozone reaction, and in some cases of late syphilis.  Daily
Syphilis (Confirmation, TP-PA) Treponema Pallidum Particle Agglutination (TP-PA) This is part of the testing algorithm to diagnose syphilis, and it is also a confirmatory test for syphilis. A reactive TP-PA test on a specimen that is also positive with a cardiolipin test suggests current or past infection with a pathogenic treponeme. All treponemal tests tend to remain reactive, probably for the life of the patient, therefore, they should not be used to evaluate response to therapy. However, false positive results can be seen. A nonreactive TP-PA test on a specimen that is reactive with a cardiolipin test is referred to as a biological false positive nontreponemal test and does not indicate syphilis. False-positive nontreponemal test results are seen in certain acute and chronic infections, following immunizations, in autoimmune disease and in intravenous drug users. A nonreactive TP-PA test on a specimen that is also nonreactive with a cardiolipin test usually indicates the absence of syphilis infection, except in incubating syphilis and in early primary syphilis, in which the TP-PA can be falsely nonreactive. For specimens that have an Inconclusive or Nonreactive interpretation with the TP-PA test we suggest submitting a second specimen in 3-4 weeks if clinically indicated.
Daily

- T -^ Top

Test

Type of Assay

Expected/Significant Results

Frequency of Testing

Toxoplasma IgG Immunoflouresence (IFA) Toxoplasma-specific IgG titers may persist for life and are therefore diagnostic only if a rising or particularly high titer (>=1:1024), is demonstrated. In such cases, the clinician should be advised to consider toxoplasmosis and attempt to identify the disesase further. Twice weekly
Toxoplasma IgM Enzyme Immunoassay (EIA) Toxoplasma-specific IgM antibodies generally persist for less than a year, therefore, demonstration of specific IgM antibodies is an indication, but not confirmation, of current or recent infection. Weekly
Typhus Immunofluoresence (IFA) A 4 fold or greater rise in titer between acute and convalescent phase sera is convincing serological evidence of recent rickettsial infection. Twice weekly
Tularemia Agglutination A single agglutination titer >1:128 or a 4 fold rise in titer between acute and convalescent phase sera, collected at least 2 weeks apart, and in the absence of previous vaccination history is diagnostic as positive for F. tularensis exposure. Weekly

- V -^ Top

Test

Type of Assay

Expected/Significant Results

Frequency of Testing

Varicella (VZV) IgG Enzyme Immunoassay (EIA) A 4 fold or greater rise in antibody titer to VZV in the absence of a similar rise to Herpes Simplex Virus is diagnostic of a current VZV infection. Weekly

- W -^ Top

Test

Type of Assay

Expected/Significant Results

Frequency of Testing

Western Equine Encephalitis (WEE) Enzyme Immunoassay (EIA) A four-fold or greater rise in titer between paired sera collected 10-14 days apart is the best evidence of recent infection. Serological cross-reactions occur with Venezuelan and Eastern Equine Encephalitis. Weekly
West Nile Virus Enzyme Immunoassay (EIA) A four-fold change in antibody titer or the presence of WN-specific IgM in CSF confirms a recent infection. Reactive IgM results in a single serum sample that is considered only presumptive evidence of recent infection, because the IgM can be detected for months after WN infection. Furthermore, serological cross-reactions with other flaviviruses (SLE  and Dengue Fever) preclude definitive diagnosis without confirmation by serum neutralization from the CDC. Weekly - by request only
Serology Tests

 

Last updated November 06, 2014