Table 5

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

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)


Testing patients for viral infection on the basis of country of origin is more sensitive and has much higher positive predictive value.

* The sample of patients available to evaluate each strategy varies because of patterns of missing data, as follows:

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;

B and C both require an initial ALT test;

D requires information on country of birth;

E and F require an initial ALT together with country of birth.

All evaluations require results of viral tests for both Hepatitis B and Hepatitis C.

ALT: Alanine aminotransferase;

LFT: Liver function test.

Arnold et al. BMC Family Practice 2011 12:9   doi:10.1186/1471-2296-12-9

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