The Accuracy of Lyme Western Blot Test for Lyme Disease: A Comprehensive Review
Imagine waking up one morning to find a strange bullseye-shaped rash on your leg. You know you've been hiking in tick-infested woods recently, so your heart sinks. Could it be Lyme disease?
The Lyme Western blot test is a blood test used to diagnose Lyme disease. It is considered one of the most specific tests for Lyme disease, but it is also the most complex and expensive. However, many researchers claim that it is not 100% accurate in diagnosing Lyme disease.
This article presents a comprehensive review of the accuracy of the Lyme Western blot test and provides a valuable resource for physicians and patients alike. It summarizes the latest research on the sensitivity and specificity of the test in different populations and stages of infection.
So, how accurate is the Lyme Western blot test? Read on to know all about it.
Lyme Western Blot Test
The Lyme Western blot test is a blood test that is used to diagnose Lyme disease. It is the most specific test for Lyme disease, but it is also more complex and expensive than other tests. The Western blot test works by detecting antibodies in the blood that are produced in response to infection with the Borrelia burgdorferi bacterium, which causes Lyme disease. Antibodies are proteins that the body produces to fight infection.
How it is performed?
To perform the Western blot test, a blood sample is drawn from the patient. The blood sample is then treated with a solution that contains proteins from the Borrelia burgdorferi bacterium. The patient's antibodies will bind to the Borrelia burgdorferi proteins if the patient has been infected with Lyme disease.
The Western blot test is performed on a strip of nitrocellulose paper. The Borrelia burgdorferi proteins are separated into different bands on the nitrocellulose paper. The patient's blood sample is then added to the nitrocellulose paper. If the patient has antibodies to Borrelia burgdorferi, the antibodies will bind to the corresponding bands on the nitrocellulose paper.
Western Blot Results
The Western blot test results are read by a trained technician. The technician looks for the presence of specific bands on the nitrocellulose paper. If the patient has at least two of the following bands, the Western blot test is considered positive:
· 23 kDa band
· 31 kDa band
· 39 kDa band
· 41 kDa band
· 93 kDa band
If the patient has one of the following bands, the Western blot test is considered indeterminate:
· 23 kDa band
· 39 kDa band
· 41 kDa band
If the patient has none of the above bands, the Western blot test is considered negative.
Lyme disease Western Blot Test Accuracy
The accuracy of the Western blot test for Lyme disease has been the subject of much research and debate. The test is highly specific, meaning that it produces very few false positive results. However, it is also less sensitive, meaning that it can produce false negative results.
The sensitivity and specificity of the Western blot test vary depending on the stage of Lyme disease and the specific test algorithm used. In general, the sensitivity of the Western blot test is higher for people with later-stage Lyme disease than for people with early-stage Lyme disease.
A 2016 meta-analysis of studies on the accuracy of the Western blot test for Lyme disease found that the mean sensitivity of the test was 62.4%. The mean specificity of the test was 98.3%.
The study also found that the sensitivity of the Western blot test increased with the stage of Lyme disease. The sensitivity of the test was 35.4% for people with early-stage Lyme disease and 64.5% for people with convalescent Lyme disease.
The specificity of the Western blot test was high across all stages of Lyme disease. The study found that the specificity of the test was 98.3% for people with early-stage Lyme disease, 99.2% for people with late-stage Lyme disease, and 99.4% for people with convalescent Lyme disease.
The study also found that the accuracy of the Western blot test was higher when the test was performed using the CDC-recommended algorithm. The CDC-recommended algorithm requires that a patient have at least two of the following bands on the Western blot test in order for the test to be considered positive:
· 23 kDa band
· 31 kDa band
· 39 kDa band
· 41 kDa band
· 93 kDa band
If a patient has only one of these bands, the Western blot test is considered indeterminate. If a patient has none of these bands, the Western blot test is considered negative.
So, we can say that the Western blot test is a highly specific but less sensitive test for Lyme disease. The accuracy of the test is higher for people with later-stage Lyme disease than for people with early-stage Lyme disease. The accuracy of the test is also higher when the test is performed using the CDC-recommended algorithm.
Limitations of Western Blot Test for Lyme Disease
The Western blot test is a highly specific test for Lyme disease, but it has a number of limitations. These limitations include low sensitivity, cross-reactivity, subjective interpretation, and complexity and cost.
Low sensitivity
The sensitivity of the Western blot test varies depending on the stage of Lyme disease. The sensitivity is lowest for people with early-stage Lyme disease, when the body has not yet had a chance to produce a strong antibody response to the infection. The sensitivity of the test increases with the stage of Lyme disease.
For people with early-stage Lyme disease, the sensitivity of the Western blot test is about 40%. This means that 60% of people with early-stage Lyme disease will have a negative Western blot test result.
For people with late-stage Lyme disease, the sensitivity of the Western blot test is about 70%. This means that 30% of people with late-stage Lyme disease will have a negative Western blot test result.
Cross-reactivity
The Western blot test can cross-react with antibodies to other diseases, such as syphilis, rheumatoid arthritis, and malaria. This can lead to false positive results.
The cross-reactivity of the Western blot test is highest for people with early-stage Lyme disease. This is because the body's immune system is still developing antibodies to the Borrelia burgdorferi bacterium, which causes Lyme disease. As a result, the immune system may also produce antibodies to other diseases.
The cross-reactivity of the Western blot test decreases with the stage of Lyme disease. This is because the body's immune system becomes more specific in its response to the Borrelia burgdorferi bacterium.
Subjective interpretation
The Western blot test results are interpreted by a trained technician. However, the interpretation of the results can be subjective, and different technicians may interpret the results differently.
The CDC has developed a set of guidelines for interpreting the Western blot test results. However, these guidelines are not always followed consistently. This can lead to different laboratories reporting different results for the same patient.
Complexity and cost
The Western blot test is more complex and expensive than other tests for Lyme disease. This is because the test requires specialized equipment and training. The complexity and cost of the Western blot test can make it less accessible to patients, especially those in developing countries.
Besides these, Western Blot test for Lyme disease cannot distinguish between active and past infection. So, it cannot be used to monitor the effectiveness of treatment. However, it is important to be aware of these limitations when interpreting the results of the Western blot test. The Western blot test should not be used as a stand-alone test for Lyme disease. It should be used in conjunction with other tests, such as the ELISA test, and the patient's clinical symptoms.