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Table 1 Accuracy of Kato-Katz method (different sampling efforts) and formalin-ether concentration technique (FECT) for the diagnosis of Clonorchis sinensis at baseline and 3 weeks after treating 74 individuals with a parasitological confirmed infection

From: Accuracy of the Kato-Katz method and formalin-ether concentration technique for the diagnosis of Clonorchis sinensis, and implication for assessing drug efficacy

Diagnostic approach

Infection intensity

Positives at baseline

Positives at 3 week post-treatment follow-up

Sensitivity [% (95% CI)]

No.

 %

Infection intensity [EPG (range)]a

No.

 % (95% CI)

Infection intensity [EPG (range)]a

Positive

False negative

Single Kato-Katzb

Light

22

29.7

266 (24–960)

20

27.0 (17.4-38.6)

89 (24–696)

n.a

n.a

Moderate

35

47.3

2,952 (1,080-8,976)

3

4.1 (0.8-11.4)

2,525 (1,512-4,224)

n.a

n.a

Heavy

17

23.0

19,555 (10,080-47,376)

0

0

n.a

n.a

n.a

Overall

74

100.0

2,229 (24–47,376)

23

31.1 (20.8-42.9)

138 (24–4,224)

17.6 (4–72)c

60.5 (43.5-75.5)

Triplicate Kato-Katzb

Light

17

23.0

295 (80–864)

26

35.1 (24.4-47.1)

60 (8–760)

n.a

n.a

Moderate

38

51.4

2,889 (1,024-9,992)

3

4.1 (0.8-11.4)

2,482 (1,984-3,136)

n.a

n.a

Heavy

19

25.7

18,390 (10,312-52,240)

0

0

n.a

n.a

n.a

Overall

74

100.0

2,750 (80–52,240)

29

39.2 (28.0-51.2)

88 (8–3,136)

16.3 (4–72)c

76.3 (59.4-88.0)

Six Kato-Katzb

Light

13

17.6

350 (124–788)

31

41.9 (30.5-53.9)

35 (4–704)

n.a

n.a

Moderate

41

55.4

3,050 (1,032-9,428)

4

5.4 (1.5-13.3)

1,808 (1,208-3,636)

n.a

n.a

Heavy

20

27.0

18,426 (10,656-31,244)

0

0

n.a

n.a

n.a

Overall

74

100.0

3390 (124–31,244)

35

47.3 (35.6-59.3)

55 (4–3,636)

n.a

92.1 (77.5-97.9)

Single FECTd

Light

51

68.9

11.7 (1–100)

13

17.6 (9.7-28.2)

3.6 (1–21)

n.a

n.a

Moderate

0

0

n.a

0

0

n.a

n.a

n.a

Heavy

23

31.1

n.a

0

0

n.a

n.a

n.a

Overall

74

100.0

n.a

13

17.6 (9.7-28.2)

3.6 (1–21)

0.7 (0.5-1)e

34.2 (20.1-51.4)f,g

Duplicate FECTh

Light

35

47.3

19.2 (2–62)

17

23.0 (14.0-43.2)

1.7 (0.5-14.5)

n.a

n.a

Moderate

22

29.7

n.a

0

0

n.a

n.a

n.a

Heavy

17

23.0

n.a

0

0

n.a

n.a

n.a

Overall

74

100.0

n.a

17

23.0 (14.0-43.2)

1.7 (0.5-14.5)

n.a

44.7 (29.0-61.5)i,j

‘Gold’ standardk

n.a

74

100.0

n.a

38

51.4 (39.4-63.1)

n.a

n.a

100.0

  1. CI, confidence interval; EPG, eggs per 1 g of stool; n.a., not applicable.
  2. aEPG is presented as geometric mean.
  3. bLight infection, 1–999 EPG; moderate infection, 1,000-9,999 EPG; heavy infection: ≥10,000 EPG.
  4. cEPG determined by six Kato-Katz thick smears.
  5. dLight infection: ≤100 EPG; heavy infection: >100 EPG.
  6. eEPG determined by duplicate FECT.
  7. fDifference in sensitivities between three Kato-Katz and single FECT determined by the McNemar test on positive individuals: p <0.001.
  8. gκ measure of agreement between three Kato-Katz and single FECT taking into account positive and negative individuals: 0.37.
  9. hLight infection: both samples ≤100 EPG; moderate infection: 1 sample ≤100 EPG and 1 sample >100 EPG; heavy infection: both samples >100 EPG.
  10. iDifference in sensitivities between six Kato-Katz and two FECT determined by the McNemar test on positive individuals: p <0.001.
  11. jκ measure of agreement between six Kato-Katz and two FECT taking into account positive and negative individuals: 0.33.
  12. kDiagnostic ‘gold’ standard is defined as a combination of six Kato-Katz and duplicate FECT.
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Parasites & Vectors

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