Non-invasive diagnosis of H pylori infection: Evaluation of serological tests with and without current infection marker CIM

Table 1 Characteristics of selected patients (n = 82)

Characteristics	n	Percentage
Age group (yr)
≤ 30	11	13.4
31-40	15	18.3
41-50	21	25.6
51-60	22	26.8
≥ 60	13	15.9
Sex
Male	49	59.8
Female	33	40.2
Smoking habit
Smoker	25	30.5
Non-smoker	57	69.5
Alcohol intake
Take alcohol	3	3.7
Do not take alcohol	79	96.3
Diabetes
Diabetic	67	81.7
Non-diabetic	15	18.3
Endoscopic diagnoses
Normal	20	24.4
Gastritis	24	29.3
Duodenitis	8	9.8
Peptic ulcer	25	30.5
Gastric carcinoma	4	4.8
Reflux esophagitis	1	1.2

Table 2 Comparison of serological tests with H pylori infection (n = 82)

Test	H pylori infection1
	Infected (n = 61)	Non-infected (n = 21)
	n (%)2	n (%)2
ELISA
Positive (n = 71)	59 (83.0)	12 (17.0)
Negative (n = 11)	2 (18.2)	9 (81.8)
ICT
Positive (n = 59)	55 (93.2)	4 (6.8)
Negative (n = 23)	6 (26.1)	17 (73.9)
ICT with CIM
Positive (n = 56)	54 (96.4)	2 (3.6)
Negative (n = 26)	7 (26.9)	19 (73.1)
Immunoblot
Positive (n = 64)	60 (93.8)	4 (6.2)
Negative (n = 18)	1 (5.6)	17 (94.4)
Immunoblot with CIM
Positive (n = 62)	60 (96.8)	2 (3.2)
Negative (n = 20)	1 (5.0)	19 (95.0)

¹Infected: Culture positive or culture negative but both RUT and histology positive; non-infected: All three tests negative;

²Percentages are over row total.

Table 3 Performance of serological tests

	Performance (95% Confidence interval) in percentage
Test	Sensitivity	Specificity	PPV1	NPV2	Accuracy
ELISA	96.7 (88.6-99.4)	42.8 (21.8-65.9)	83.1 (72.3-90.9)	81.8 (48.2-97.7)	82.9 (73.0-90.3)
ICT	90.1 (79.8-96.3)	80.9 (58.0-94.5)	93.2 (83.5-98.1)	73.9 (51.5-89.7)	87.8 (78.7-93.9)
ICT with CIM	88.5 (77.7-95.2)	90.4 (69.6-98.8)	96.4 (87.6-99.5)	73.0 (52.2-88.4)	89.0 (80.1-94.8)
Immunoblot	98.3 (91.2-99.9)	80.9 (58.0-94.5)	93.7 (84.7-98.2)	94.4 (72.7-99.8)	93.9 (86.3-97.9)
Immunoblot with CIM	98.3 (91.2-99.9)	90.4 (69.6-98.8)	96.7 (88.8-99.6)	95.0 (75.1-99.8)	96.3 (89.6-99.2)

¹PPV: Positive predictive value;

²NPV: Negative predictive value.