In a surveillance centre for Hepatitis B,in a low prevalance area,the method for testing for Hepatitis B was single ELISA.This policy was changed to double testing in series.This would result in the following 2 parameters of the test being affected:

• A. Sensitivity and negative predictive value
• B. Specificity and negative predictive value
• C. Specificity and positive predictive value
• D. Sensitivity and positive predictive value