Step I UW Error: Biostats?

[DMBFan]

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Here is a question on USMLE World that I think may be an error.

A new test to diagnose a UTI in women is being evaluated. The gold standard is a positive urine dipstick plus urine culture. Results are given below:

+ Dipstick + UC - Dipstick + UC
Test 60 20
+
- 440 180

What is the new test's specificity?
A. 10
B. 30
C. 56
D. 70
E. 90

I got 90% from my calculations of specificity. However, UW says that the specificity would be 90% and then goes on to give the predictive value of 10%. Is this an error or am I missing something?

 

[osli]

For the numbers you gave (and if I am interpreting their positions correctly - format is hard to follow)

Sensitivity 12%
Specificity 90%
PPV 75%
NPV 29%

So yeah, specificity is .9 if that is what they asked for. But your last statement confused me... were they asking for a specificity or a predictive value? Neither would be 10% though, so probably a typo.