Lyme Disease Testing Now Employs a Two-tiered Antibody Standard
The CDC recommends a two-step process for testing blood for Lyme disease. The two steps can be
performed on the same blood sample and are designed to be performed
together. The CDC further states that to skip the initial test and
only perform the Western blot is not recommended: “Doing so
will increase the frequency of false-positive results and may lead to
misdiagnosis and improper treatment.”*
Effective August 11, 2014, LabCorp will offer only a two-step test process for Lyme disease antibody testing. The first step is an initial enzyme immunoassay (EIA), with reflex of any equivocal and positive test results to the second step, a Western blot assay. All single-step screening test options (those without the supplemental reflex) will be discontinued. Specimens that result as negative by an EIA assay do not require further testing. Specimens that result as equivocal or positive will not be reported until the supplemental test is performed.
The discontinuation of the single-step process applies to all Lyme disease test numbers. If you currently use a custom profile that
Effective August 11, 2014, LabCorp will offer only a two-step test process for Lyme disease antibody testing. The first step is an initial enzyme immunoassay (EIA), with reflex of any equivocal and positive test results to the second step, a Western blot assay. All single-step screening test options (those without the supplemental reflex) will be discontinued. Specimens that result as negative by an EIA assay do not require further testing. Specimens that result as equivocal or positive will not be reported until the supplemental test is performed.
The discontinuation of the single-step process applies to all Lyme disease test numbers. If you currently use a custom profile that
includes a single-step Lyme test process, please contact your LabCorp
representative as soon as possible to update the custom profile.
At this time, LabCorp is also changing the kit manufacturer for the EIA Lyme antibody test. The new reagent for total antibody reports an immunoglobulin status ratio (ISR), identified as negative, equivocal, or positive. The IgM test will report an index value that is classified as negative, equivocal, or positive. Although these adjustments will affect some EMR systems (see note below), they should not affect clinical decision making.
FOR THE FULL ARTICLE: (page 8)
At this time, LabCorp is also changing the kit manufacturer for the EIA Lyme antibody test. The new reagent for total antibody reports an immunoglobulin status ratio (ISR), identified as negative, equivocal, or positive. The IgM test will report an index value that is classified as negative, equivocal, or positive. Although these adjustments will affect some EMR systems (see note below), they should not affect clinical decision making.
FOR THE FULL ARTICLE: (page 8)
1 comment:
You're almost right. The actual first test is an ELISA test, not EIA test. You're using old information from 2011...
The Enzyme-linked immunosorbent assay (ELISA) test is used most often NOT to detect Lyme disease, but instead, the antibodies to B. burgdorferii (the bacterial spirochete that causes Lyme disease). Because it can sometimes provide false-positive results, it's not used as the sole basis for diagnosis. This test may not be positive during the early stage of Lyme disease, but the rash is distinctive enough to make the diagnosis without further testing in people who live in areas infested with ticks that transmit Lyme disease.
If the ELISA test is positive, another test — the Western blot — is usually done to confirm the diagnosis. In this two-step approach, the Western blot detects antibodies to several proteins of B. burgdorferi.
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