A patient with RA and pneumonia tested positive for Mycoplasma pneumoniae at titer 1:32, but three weeks later, the titer remains unchanged. What best explains this?

A patient with RA and pneumonia tested positive for Mycoplasma pneumoniae at titer 1:32, but three weeks later, the titer remains unchanged. What best explains this?

• A. IgM-specific antibodies do not increase fourfold
• B. The results are not significant because the initial titer was not accompanied by a positive test for cold agglutinins
• C. Rheumatoid factor caused a false-positive test result
• D. Insufficient time had elapsed between measurements

Answer: (C)

In this scenario, the correct explanation revolves around the potential interference of rheumatoid factor (RF) in laboratory testing for Mycoplasma pneumoniae. A positive test for Mycoplasma pneumoniae at a titer of 1:32 indicates that the patient has been exposed to the organism; however, when testing for antibodies develops, RF can cause a false-positive result. This is particularly relevant in patients with rheumatoid arthritis (RA), who often have elevated RF levels due to their autoimmune condition. In the context of the question, if the patient remains symptomatic or has not shown a significant decrease in disease status despite the positive result, it suggests that the titer may not accurately reflect an active infection. Instead, the persistent titer may be a consequence of RF's interference with the serological test for Mycoplasma pneumoniae, leading to misinterpretation of the patient's immune response. Analyzing the other options provides insights into why they do not adequately explain the situation. The suggestion that IgM-specific antibodies do not increase fourfold generally references specific dynamics of antibody responses in certain infections, but this does not address the specific scenario present in this case. Regarding the second option, the absence of cold agglutinins may not significantly impact the overall

In this scenario, the correct explanation revolves around the potential interference of rheumatoid factor (RF) in laboratory testing for Mycoplasma pneumoniae. A positive test for Mycoplasma pneumoniae at a titer of 1:32 indicates that the patient has been exposed to the organism; however, when testing for antibodies develops, RF can cause a false-positive result. This is particularly relevant in patients with rheumatoid arthritis (RA), who often have elevated RF levels due to their autoimmune condition.

In the context of the question, if the patient remains symptomatic or has not shown a significant decrease in disease status despite the positive result, it suggests that the titer may not accurately reflect an active infection. Instead, the persistent titer may be a consequence of RF's interference with the serological test for Mycoplasma pneumoniae, leading to misinterpretation of the patient's immune response.

Analyzing the other options provides insights into why they do not adequately explain the situation. The suggestion that IgM-specific antibodies do not increase fourfold generally references specific dynamics of antibody responses in certain infections, but this does not address the specific scenario present in this case. Regarding the second option, the absence of cold agglutinins may not significantly impact the overall