This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Screening, Subject name: Social & Preventive Medicine
Calculate positive predictive value of ELISA test for HIV with sensitivity 99%, specificity 99%. Prevalence of HIV in population is 5/1000. 
Select and explain. 
A. 10, B. 70, C. 34, D. 99
C: 34
Answer: C: 34 
Explanation: Ref :Parks 23rd edition pg139 Construct a 2x2 table using the above data. 4.95 9.95 0.05 985.05 PPV = TP / (TP + FP) = 4.95/(4.95+9.95)=0.34