In reply:
We thank Dr McEvoy for his thoughtful reply to our report. He is correct that our definition of false positive was restrictive; however, we based this definition on the manufacturer's stated accuracy specification, and, indeed, found that the RAD-57 functioned as specified. When broadened to include 2 standard deviations (95% of the data), the accuracy range would be ± 6%, a range that is challenging for the purpose of diagnosing CO poisoning.
We readily acknowledge that technician technique may play a role in obtaining accurate data, even though our technicians and study team were trained by the manufacturer on probe placement. Our concern is that, whether by technical limitations or operator error, the RAD-57 may provide an erroneously low SpCO measurement in a patient with CO poisoning. We agree that SpCO technology can be valuable in broadly screening for occult CO poisoning. We offer that an elevated SpCO should raise concern about CO poisoning, especially if the evaluating clinician has not considered CO exposure. However, we strongly caution against using SpCO measurement to rule out CO poisoning when symptoms and circumstances suggest it. Returning a misdiagnosed patient to the scene of the poisoning can have devastating and even deadly consequences.
Footnotes
The authors have disclosed relationships with SciMetrika and Masimo.
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