Skip to main content

Advertisement

Table 5 Yield, sensitivity and Positive Predictive Values (PPV) of different detection strategies

From: Should patients with abnormal liver function tests in primary care be tested for chronic viral hepatitis: cost minimisation analysis based on a comprehensively tested cohort

Strategy for viral testing No. of patients* Hepatitis cases* Viral tests Cases detected Sensitivity (%) PPV (%) 95% Confidence Limits
A. If repeat LFT panel is abnormal 1124 11 955 11 100 1.15 (0.64-2.05)
B. If ALT abnormal on primary test 1064 12 418 8 67 1.91 (0.97-3.73)
C. If ALT > 2 upper limit of normal on primary test 1064 12 77 6 50 7.79 (3.62-15.98)
D. If patient born in a country of intermediate to high viral hepatitis prevalence. 1208 13 170 11 85 6.47 (3.65-11.21)
E. If patient born in a country of intermediate to high viral hepatitis prevalence and ALT > 2 upper limit of normal on primary test. 1041 12 16 5 42 31.25 (14.16-55.60)
F. If patient born in a country of intermediate to high viral hepatitis prevalence, or ALT > 2 upper limit of normal on primary test. 1041 12 215 11 92 5.12 (2.88-8.93)
G. Test all cases 1236 13 1236 13 100 1.05 (0.62-1.79)
  1. Testing patients for viral infection on the basis of country of origin is more sensitive and has much higher positive predictive value.
  2. * The sample of patients available to evaluate each strategy varies because of patterns of missing data, as follows:
  3. A requires a complete panel of follow-up LFTs, the missing data in the two cases that were not abnormal might have led to an exagerated estimate of sensitivity;
  4. B and C both require an initial ALT test;
  5. D requires information on country of birth;
  6. E and F require an initial ALT together with country of birth.
  7. All evaluations require results of viral tests for both Hepatitis B and Hepatitis C.
  8. ALT: Alanine aminotransferase;
  9. LFT: Liver function test.