Skip to main content

Table 3 Selected outcomes from applying 1- and 2-test diagnostic strategy models to three HBV epidemic scenarios. The examples here have been extracted from Additional file 1

From: One or two serological assay testing strategy for diagnosis of HBV and HCV infection? The use of predictive modelling

Population: 10,000        
  Strategy HBsAg Test Kit True Positive False Positive False Negative PPV number of assay B tests
Scenario 1 Prevalence 10%: 1-test 1 980 90 20 0.916  
2-test 1 → 6 960 1 40 0.999 1070
1-test 2 900 90 100 0.909  
2-test 2 → 5 810 1 190 0.999 990
Scenario 2 Prevalence 2%: 1-test 1 196 98 4 0.667  
2-test 1 → 6 192 1 8 0.995 294
1-test 2 180 98 20 0.647  
2-test 2 → 5 162 1 38 0.994 278
Scenario 3 Prevalence 0.4% 1-test 1 39 100 1 0.282  
2-test 1 → 6 38 1 2 0.975 139
1-test 2 36 100 4 0.265  
2-test 2 → 5 32 1 8 0.970 136
Test Kit Performance Characteristics:  
Test Kits Sensitivity Specificity      
1 and 6 98.0% 99.0%      
2 and 5 90.0% 99.0%      
Notes on Two-Test Strategies:
Assay B performance is considered independent of Assay A  
Outcome of 2-test strategy: A + B+ = pos and A-, A + B- = neg (Fig. 2)  
2-test strategies overall performance: Assay A Assay B Sensitivity Specificity
     1 6 96.04% 99.99%
     2 5 81.00% 99.99%