Some times we want to conduct a reliability study on some diagnostic modality for a specific disease but the gold standard for the diagnosis of that disease is either invasive procedure or surgery. which is not justified to be performed on normal individuals (control group). In such a case is it justified to take control group as negative of the gold standard?
For example:
We want to diagnose Infantile Hypertrophoid pyloric stenosis (IHPS) with the help of ultrasound but the gold standard for its diagnosis is surgery. If we perform Ultrasound of 50-infants with projectile vomiting and the sonographic findings of 40 of them are likely for IHPS and 10 for normal. But after surgery (Gold-Standard) 38- were confirmed as IHPS but 2 were false positive. Now we want to perform ultrasound of 50-normal (control). Is it justified to put all the 50 normal infant as True negative and false positive as 0 of the gold Standard, To perform chi-Square statistics?
Hello,
If I well undertood your question, I think here you can use the Bayes Theorme, based on clinic litterature if you have about this specific test. we can consider the ultrasound results as a priori information about the clinic test, and the Gold-standard one as the real data (x).
I can reformulate your problem as :
If your test results come back positive when using ultrasound method, what are your chances that children actually have the disease (with G-S method) ?
CHELLAI. F
If it is possible to adjust to gold standard results then you have a reasonable hope. Otherwise I don't see it. Remember if you do that you should be able to take the probability that your adjustment is wrong into account. I recommend talking to an experimental design person who is in this area. Best, D. Booth
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