A new test for hepatocellular carcinoma is being developed. The test is administered to 1,000 patients with hepatocellular carcinoma and 1,000 patients without hepatocellular carcinoma. Of the 1,000 patients with hepatocellular carcinoma, 900 have a positive result. Of the 1,000 patients without hepatocellular carcinoma, 125 have a positive result. Evaluate diagnostic tests: specificity, sensitivity, PPV, NPV, prevalence. Diseased group Non-diseased group Total "+" test result 900 (a; TP) 125 (b: FP) 1,025 "-" Test result 100 (c; FN) 875 (d; TN) 975 Total 1,000 1,000 N = atb+c+d 2000 1. SP = d/b+d = 875/1000 = 87.5% 2. SE= a/a+c = 900/1000 = 90% 3. PPV = a/a+b = 900/1,025 = 88% 4. NPV = d/c+d= 875/975 = 89% 5. Prevalence = a+c/N = 1,000/2,000 = 50%