Best Lyme Disease Test
Antibodies to Borrelia burgdorferi, the bacteria that causes Lyme Disease do not appear in the blood until several weeks (usually 4-6 weeks) after the tick bite. The Lyme bacteria are not always present in the blood. A patient could have been infected with a strain of Bb that is not covered in testing.
The ELISA (Enzyme-Linked Immunosorbent Assay) and Elctrophoresis-based and Western blot (also known as Immunoblot) are the most common tests used to diagnose Lyme disease. Both tests measure antibodies made by the immune system to fight infection to Borrelia burgdorferi.
Both the ELISA and Western blot can only detect whether a person has been exposed to Borrelia burgdorferi. The tests cannot determine if there is an active infection which could be causing the persisting symptoms since antibodies can be produced for months or years after an infection has cleared.
Typically, the ELISA test is used to initially screen for Lyme disease. If negative, the clinician may dismiss the possibility of a Lyme disease diagnosis and choose not to perform the Western blot. However, the ELISA is not an accurate screening test. Numerous studies have found it to have a poor sensitivity rate.Thus doing an ELISA AND WESTERN BLOT give the best sensitivity and specificity. This is called the two-tier test. The probability of a false-negative test for Lyme with a single test for early-stage disease was high at 66.8%.
Other disease than can give you a false positive Lyme: a tick-borne relapsing fever, infection with Treponema denticola, Treponema pallidum, Epstein–Barr virus, Anaplasma spp., Leptospira spp., or Helicobacter pylori.
Second National Conference on Serologic Diagnosis of Lyme Disease in 1994 and associated workshops and recommended for disease surveillance by the US Centers for Disease Control and Prevention (CDC), and for clinical diagnosis by a review panel at that time. The procedure uses the two tests in a sequential fashion with the ELISA test being the first step (or, less commonly, an immunofluorescence assay). Positive or equivocal samples are then subjected to a confirmatory WB test this can be carried out on the same sample as used for the first step. If the first step is negative, the second step is not carried out. Furthermore, the CDC recommends that one should not jump straight to the second step without carrying out the first step. But most doctors do both if the suspicion is high.
References:
When a patient suspected with juvenile idiopathic arthritis turns out to be diagnosed with an infectious disease – a review of Lyme arthritis in children.
Abstract
The Lyme arthritis is a common manifestation of infection with Borrelia burgdorferi spirochete. Despite its infectious background, the inflammation clinically and histopatologically resembles juvenile idiopathic arthritis. As it affects a considerable number of Lyme disease patients, it should be routinely considered in differential diagnosis. Development of arthritis is partially dependent on spirochetal factors, including the ribosomal spacer type and the sequence of outer surface protein C. Immunological background involves Th1-related response, but IL-17 provides an additional route of developing arthritis. Autoimmune mechanisms may lead to antibiotic-refractory arthritis. The current diagnostic standard is based on a 2-step testing: ELISA screening and immunoblot confirmation. Other suggested methods contain modified two-tier test with C6 ELISA instead of immunoblot. An initial 28-day course of oral antibiotics (doxycycline, cefuroxime axetil or amoxicillin) is a recommended treatment. Severe cases require further anti-inflammatory management. Precise investigation of new diagnostic and therapeutic approaches is advisable.
Int J Gen Med. 2017 Apr 10;10:113-123. doi: 10.2147/IJGM.S131909. eCollection 2017.
Application of Bayesian decision-making to laboratory testing for Lyme disease and comparison with testing for HIV.
Abstract
In this study, Bayes’ theorem was used to determine the probability of a patient having Lyme disease (LD), given a positive test result obtained using commercial test kits in clinically diagnosed patients. In addition, an algorithm was developed to extend the theorem to the two-tier test methodology. Using a disease prevalence of 5%-75% in samples sent for testing by clinicians, evaluated with a C6 peptide enzyme-linked immunosorbent assay (ELISA), the probability of infection given a positive test ranged from 26.4% when the disease was present in 5% of referrals to 95.3% when disease was present in 75%. When applied in the case of a C6 ELISA followed by a Western blot, the algorithm developed for the two-tier test demonstrated an improvement with the probability of disease given a positive test ranging between 67.2% and 96.6%. Using an algorithm to determine false-positive results, the C6 ELISA generated 73.6% false positives with 5% prevalence and 4.7% false positives with 75% prevalence. Corresponding data for a group of test kits used to diagnose HIV generated false-positive rates from 5.4% down to 0.1% indicating that the LD tests produce up to 46 times more false positives. False-negative test results can also influence patient treatment and outcomes. The probability of a false-negative test for LD with a single test for early-stage disease was high at 66.8%, increasing to 74.9% for two-tier testing. With the least sensitive HIV test used in the two-stage test, the false-negative rate was 1.3%, indicating that the LD test generates ~60 times as many false-negative results. For late-stage LD, the two-tier test generated 16.7% false negatives compared with 0.095% false negatives generated by a two-step HIV test, which is over a 170-fold difference. Using clinically representative LD test sensitivities, the two-tier test generated over 500 times more false-negative results than two-stage HIV testing.
