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#1
03-28-2015
 USMLE Forums Guru Steps History: Not yet Posts: 304 Threads: 76 Thanked 73 Times in 51 Posts Reputation: 83
confusing concept on biostatistic

Sensitivity rule out disease BUT also it detects ppl with diseases isn't opposite !!
Confused

#2
03-28-2015
 USMLE Forums Newbie Steps History: Not yet Posts: 1 Threads: 0 Thanked 1 Time in 1 Post Reputation: 11

test---- positive-----negative
disease--- A --------- B
-------------------------------------
healthy--- C --------- D

sensitivity = A / A+B
= true positive rate (TPR) = TP / TP+FN
=how many people who really have the DISEASE are Detected (hit rate)

when sensitivity = 100% = 1
B = FN = 0, thus a negative result must be true (rule out... "SNOUT")

and vice versa for "SPIN" (FP=0)

hope that helped : )
 The above post was thanked by: swwal (03-29-2015)
#3
03-28-2015
 USMLE Forums Addict Steps History: 1+CK+CS Posts: 122 Threads: 17 Thanked 128 Times in 39 Posts Reputation: 138

Used to rule out disease is how the sensitive tests are used clinically.
If u use a sensitive test (100%) on a patient and it comes back negative then ths patient is very unlikely to have the disease (ie ruled out).. In ths case u can actually say that the patient doesn't have ths particular disease.

On the other hand if the test is positive , it is of no value and u have to confirm with a specific test.
 The above post was thanked by: swwal (03-29-2015)
#4
03-29-2015
 USMLE Forums Guru Steps History: Not yet Posts: 304 Threads: 76 Thanked 73 Times in 51 Posts Reputation: 83

What's significance of this
sensitivity = 1 - FN rate

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