The culture of B. burgdorferi from specimens in Barbour Stoenner-Kelly medium permits a definitive diagnosis. With a few exceptions, positive cultures have only been obtained early in the illness, primarily from biopsy samples of EM lesions, less often from plasma samples, and only occasionally from CSF samples in patients with meningitis. Later in the infection, polymerase chain reaction (PCR) testing is superior to culture for the detection of B. burgdorferi in joint fluid.

In the United States, the diagnosis is usually based on the recognition of the characteristic clinical findings, a history of exposure in an area in which the disease is endemic and, except in patients with EM, an antibody response to B. burgdorferi. In more than 50% of cases, physicians are comfortable making the diagnosis based on symptoms and patient history. Testing becomes important when the telltale bull’s eye rash or other symptoms characteristic of Lyme disease do not appear (Table 1).

Table1.  Methods of Lyme Disease Detection

Antibody Detection

 Assays for the detection of antibodies to B. burgdorferi are the most practical means for confirming infection. The CDC currently recommends a two-step process when testing blood for evidence of antibodies against the Lyme disease bacteria. Both steps can be done using the same blood sample. The first step uses an enzyme immunoassay (EIA) or, rarely, an indirect immunofluorescence assay (IFA). If the first step is negative, no further testing of the specimen is recommended. If the first step is positive or indeterminate (sometimes called equivocal), the second step should be per formed. The second step uses an immunoblot procedure, commonly, a Western blot test. Results are considered positive only if the EIA-IFA and the immunoblot test results are both positive.

The two steps of Lyme disease testing are designed to be done together. CDC does not recommend skipping the first test and just doing the Western blot test. Doing so will increase the frequency of false-positive results and may lead to misdiagnosis and improper treatment.

Enzyme-Linked Immunosorbent Assay

The enzyme-linked immunosorbent assay (ELISA) is the standard test method; it is the most widely available and frequently performed test. The sensitivities of IFA and ELISA methods are usually low during the initial 3 weeks of infection; therefore, negative results are common. The most serious disadvantages of current techniques are low sensitivity and lengthy processing time. In addition, false-positive reactions can result from cross-reactivity in tests for Lyme disease. For example, tick-borne relapsing fever spirochetes, Borrelia hermsii, are closely related to B. burgdorferi. Antibodies to B. hermsii, an agent that coexists with the Lyme disease spirochete in portions of the western United States, strongly cross-react with B. burgdorferi in IFA staining and ELISA testing. Common antigens are shared among the Borrelia organisms and even with the treponemes. Serum from syphilitic patients reacts positively in assays for Lyme disease. Therefore, serologic test results for antibodies to B. burgdorferi should be considered along with clinical data and epidemiologic information when a patient is evaluated for Lyme disease.

Western Blot Analysis

 Western blot analysis can verify reactivity of antibody to major surface or flagellar proteins of B. burgdorferi (Fig. 1). The Western blot test is helpful in determining borderline negative or weakly positive results obtained from other tests, but the values are not always reliable. This procedure is more definitive in later Lyme disease when multiple antibody bands specific for B. burgdorferi appear. Reported results from West ern blot tests for Lyme disease in its late phase indicates reactive bands for IgM levels. The 41-kDa bands are the earliest to appear, but can cross-react with other spirochetes. The 18-, 23- to 25- (Osp C), 31- (Osp A), 34- (Osp B), 37-, 39-, 83-, and 93-kDa bands are the most specific, but may appear later or not appear at all.

Fig1. Example of immunoblot calibration. Lane 1,  Monoclonal antibodies defining selected antigens to B. burgdorferi B31 separated in a linear SDS-PAGE gel Marblot (MarDx  Diagnostics, Carlsbad, Calif). Lane 2, Human serum (IgG) reactive  with the 10 antigens scored in recommended criteria for blot scoring; lines indicate other calibrating antibodies. Molecular  masses are in kilodaltons. Osp, Outer surface protein. (From Det rick B et al, editors: Manual of molecular and clinical laboratory immunology, ed 7, Washington, DC, 2006, American Society for Microbiology Press, p 499.)

Polymerase Chain Reaction

PCR testing can detect spirochetes in the synovial fluid around the joints or in other clinical samples. The PCR assay looks for DNA of the organism. In the past, positive PCR assay results were taken as definitive evidence that a person had an infection, but it is possible to have antigens in the presence of nonviable organisms. This test amplifies small amounts of DNA that may remain, even when intact organisms are no longer present, an indication that the organism does or did exist. The PCR assay may miss the spirochete in the blood, allowing it to move into other tissues.

The PCR technique directly identifies the pathogen instead of measuring the host’s immune response to it. It can detect DNA from as few as one to five organisms, even those that are nonviable. Different specific probes have been developed and the PCR assay has been used to detect B. burgdorferi DNA in a variety of body fluids. The appeal of the PCR method lies in its rapid turnaround time (2 days versus 6 to 8 weeks for culture) and avoidance of the difficulties associated with culture or immunohistochemistry. It has very high specificity, but the sensitivity may be as low as 70%. The PCR test may be useful in diagnosing early Lyme disease when the patient is still seronegative.

Cerebrospinal Fluid Analysis for Antibody Detection

 Spinal taps are not routinely recommended; a negative tap does not rule out Lyme disease. Antibodies to B. burgdorferi can be detected in the CSF in only 20% of patients with late disease. Therefore, spinal taps are performed only on patients with pronounced neurologic manifestations. The goal is to rule out other conditions and determine whether B. burgdorferi antigens are present. It is especially important to look for elevated protein levels and mononuclear cells, which would dictate the need for more aggressive therapy, and to check the opening CSF pressure, which can be elevated and contribute to headaches, especially in children.

اخر الاخبار

اخبار العتبة العباسية المقدسة

فرقة العباس تنظم مجلس عزائها السنوي بذكرى شهادة النبي (صلى الله عليه وآله) في النجف

قسم الشؤون الفكرية وجامعة الكوفة يعقدان شراكة علمية لتدريب الطلبة على صيانة المخطوطات وحفظها

بالتزامن مع ذكرى شهادته.. قسم الشؤون الفكرية يصدر كتابًا عن النبي الأعظم (صلى الله عليه وآله)

بالصور.. جموع المؤمنين تحيي ذكرى شهادة الرسول الأكرم عند مرقد الإمام علي (صلوات الله عليهما)

المزيد

الآخبار الصحية

لون أسنانك يتحدث عن صحتك.. إليك ما يقول

عادة يومية بسيطة تخفض الكوليسترول وتحمي القلب

الزنجبيل.. دواء سحري لحماية القلب

المشروبات شديدة السخونة.. "خطر خفي" يهدد صحتك

المزيد

الآخبار التكنلوجية

كيف يمكن لعادات القيادة السيئة أن تؤثر على قيمة سيارتك

في طوفان الذكاء الاصطناعي.. نصائح لحجز "تذكرة النجاة"

هكذا يسرق "قراصنة الذكاء الاصطناعي" المليارات بطرق بسيطة

فيديو لانفجار كرة نارية في سماء اليابان.. ما تفسير ذلك؟

المزيد

مواضيع ذات صلة

rheumatoid factor (RF)

reticulocyte count (Retic count)

red blood cell indices (RBC indices, Blood indices)

NGAL

Biomarkers of Tubulo-Interstitial Injury

Low-Molecular-Weight Plasma Proteins

Immunofluorescence Assay (IFA)

Enzyme-Linked Fluorescent Assay (ELFA)

red blood cell count (RBC count, Erythrocyte count)

rabies-neutralizing antibody test

prothrombin time (PT, Protime, International normalized ratio [INR])

Estimation of the Glomerular Filtration Rate by Equations