Specificity = 63,650/64,633 = 98.5%

Positive Predictive Value = 132/1,115 = 11.8%

Negative Predictive Value = 63,650/63,695 = 99.9%

You can improve sensitivity and specificity by using more than one screening test, using multiphasic screening and targeting high risk populations

If prevalence of a disease is low, even a highly valid test will yield a low predictive value