Naked Science: Conflicting Lab Results & How They Should Be Handled
At CLEAR we believe transparency is crucial. Since the announcement of the European strain of Chlamydia back in November, we have had lots of questions about how we identified the strain and what laboratories should do in case their results conflict with another laboratory.
This post outlines the steps most laboratories take to verify the accuracy of their results as well as how we identified the Chlamydia strain among our patient population.
What is a correlation study?
A correlation study is a comparison of two or more laboratory tests or instruments against each other. It is used to validate the accuracy of a test and/or platform. This type of study is a standard practice among all laboratories.
Why is it important?
In science, variables are common. No matter the methods being used or how long a laboratory has been in business, one cannot assume it is using “the best method” or that its findings cannot be contested. By examining differing methods or scenarios, we can more accurately define the true performance of a test (or methodology, in lab speak). The best way to ensure accuracy is to eliminate any potential issues that may be part of the process and to focus on the science behind how it’s done.
How is it useful?
In situations where there are conflicting results, a correlation study can help isolate probable causes and allows the laboratory to determine the nature of the problem, and in some cases whether there is a problem at all. Correlation studies are commonly done “blind”, in other words, without each party knowing the expected outcome. This allows the findings to be completely impartial.
How is it performed?
Step 1: Correlation studies begin internally by identifying any probable causes of variance within the lab itself. Items to evaluate include a review of all policies and procedures, staff retraining, consideration of environmental factors, etc.
Step 2: To send specimens out to an impartial laboratory that will look at only the science and not be biased in any way. This is accomplished by the “blind” element of the study - the other laboratory should have no reference to the expected results - positive, negative, non-reactive, etc. This allows them to focus only on the scientific portion and deliver accurate clinical results.
Step 3: Depending on the outcome of Step 2, this third step may involve confirmation by highly-sensitive testing, to verify the findings on a molecular level. This serves to disciple any potential notion of result inaccuracy by isolating specific compounds that can confirm the initial lab findings.
Do all labs do this?
Most do. Recently, CLEAR was made aware of discrepant results on Ct/Ng and followed the steps outlined above. By doing so, we were able to identify that the discrepancies were not discrepancies at all, but instead, true positive results caused by a new variant of Ct/Ng that is not detectable using normal lab methods. The findings of this recent correlation study are available below.
What happens if a lab does not perform correlation studies?
Molecular testing is not a black-and-white science. So while laboratories are not required to do correlation studies when questions arise about the accuracy of their test results, it is considered best practice