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if upper limit of glucose value is decrease ........
a. decrease specificity
b.decrease sensitivity
c.increase PPV
d.decrease NPV
e. no change
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so let say the upper part is from 110 you lowwer it to 100 ..so the criteria of diagnosing DM will be stricter, so are we going to catch more DM or are more people going to test positive ,,
so I will assume that peole who tets positive will actually hav ethe disease, so it will increase the PPV ???????????????????
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Is it like with the cutoff point of USMLE -STEP 1 ???
the mor ecut-off the less peole will pass..??
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PPV= TP/TP+FP
if u lower the upper limit false positive is increase , so how come .....PPV increase .......according to formula......
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I don't know ..I don't undrstund this logic...I am just thinking loud !!!!!!!!
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PPV and NPV are affected by prevalance ,usually whenever we either increase or decrease a cut off value it is the sensitivity ans specificity which is affected .When cut off value is decreased ,we are going to diognose more pts with the disease..i think it will affect the sensitivity of the test..so will decrease the sensitivity
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IF YOU LOWER THE VALUE FOR GLUCOSE CUT OFF YOU DECREASE THE SENSITIVITY
actually the value for Glucose was increased to 126mg/dl, so that the people that have these values have trully DM , SO INCREASE SENSITIVITY...
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what will be the affect on specificity???
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if u lower the upper value .... sensitivity increase , NPV increase, decrease specificity,decrease PPV.
correct me , if i was wrong ......