Throat Culture vs Rapid Strep Test: Which one is more accurate?
Sore throat is a common ailment that can be caused by either a viral or bacterial infection. However, it is difficult for physicians to diagnose the underlying cause of the sore throat, as the symptoms are usually similar in both cases. In most cases, a throat culture or a rapid strep test is performed to confirm the diagnosis. Both methods are used to detect the presence of group A Streptococcus (GAS), the bacteria responsible for strep throat. But which one is more accurate? Let’s take a closer look.
Introduction:
Sore throats caused by bacteria require antibiotics, making it imperative to pinpoint the responsible pathogen for proper treatment. While sore throats are caused by both viruses and bacteria, it’s not always easy to determine the underlying cause. Throat culture and rapid strep tests are two very effective methods to diagnose strep throat, but which one gives the more accurate result?
Throat Culture:
A throat culture is considered the gold standard for diagnosing strep throat, as it has been in use for almost a century. During this procedure, a sterile swab is inserted inside the patient’s mouth to collect a sample from the throat. The collected sample is then transferred to a laboratory where it is incubated for a couple of days. The sample is then tested for the presence of GAS bacteria through bacterial cultures that are grown on agar plates. If the plates are clean, the throat culture is negative, and if there’s bacterial growth, it is positive.
Rapid Strep Test:
The rapid strep test (also known as a throat swab) was introduced in the early 1990s. It is a quick test that takes only a few minutes to perform and produces results in just a few minutes. The rapid strep test involves the collection of a throat sample using a sterile swab, which is then placed inside a reagent test. If there is any presence of the GAS bacteria, the test will change color, indicating a positive result. The rapid strep test is also known as a rapid antigen detection test (RADT).
Which one is more accurate?
Studies have shown that throat cultures are more accurate than rapid strep tests. Throat cultures can detect even very low levels of GAS, making the results more reliable. However, the downside to this test is that it takes a longer time, usually two to three days for a reliable result. Rapid strep tests, on the other hand, are less reliable, with a higher chance of false negatives. This test requires a lot of diligence as it searches for the antigen. Users would have to ensure they avoid swabbing the wrong part of the throat. The rapid test results are known to have higher rates of false negatives, mostly when GAS levels are low.
Conclusion:
While rapid strep testing is quicker and less expensive than throat cultures, it is not as accurate, making it best to use when rapid results are needed, and there is a high suspicion of the disease. Throat cultures, although more time-consuming and invasive, are more reliable. The key is obtaining an accurate representation of a bacterial sample to detect the presence of GAS bacteria. However, there remain some disadvantages for throat culture tests such as the issue of culturing pathogens that could inhibit the growth of other microbes, hence preventing GAS’s growth. Therefore, the decision to select which test to use should rely on individual situations. When in doubt, consulting primary healthcare specialists can assist in determining the best diagnostic approach for a sore throat.
