A 57-year-old man with a history of bleeding per rectum visits his physician to discuss the results of his recent CT colpography test. The test was positive for the presence of a colorectal polyp. The sensitivity and specificity of this test to detect a colorectal polyp is 75% and 90% respectively.

What is the probability that this patient indeed has a colorectal polyp?

A – 92%

B – 90%

C – 88%

D – 86%

E – 84%

**Answer**

Positive predictive value of the test is the probability that a patient with a positive test indeed has a disease. This patient has a positive test. To estimate the PPV of the test we must draw a 2×2 table.

RPV = TP/all positive (TP+FP)

= 75/75+10

= 75/85

= 88%

The correct answer is C

We got 3 Correct answers. Drawing is done and the winner is **Mina Shehata**

Congratulations and better luck for all of you on next question

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Esan Ah says

B

Dr Ray Makar says

Thank you Dr Esan

Peter says

A

Dr Ray Makar says

Thank you Dr Peter

Rutamirika Evans says

Answer is 84

Dr Ray Makar says

Thank you Dr Evans

Ajith Ravindran says

84%

Dr Ray Makar says

Thank you Dr Ajith

Shaili says

C-88%

Shaili says

C- 88%

Dr Ray Makar says

Thank you Dr Shaili

Ehab Anter says

84% The answer is E

Dr Ray Makar says

Thank you Dr Ehab

Mike kempton says

C 75/85 = 88%

Dr Ray Makar says

Thank you Dr Mike

Mina Shehata says

C -88%

Dr Ray Makar says

Thank you Dr Mina

Ahmed Taha Darweesh says

ANSWER: B- 90%

Dr Ray Makar says

Thank you Dr Ahmed