Follow-up investigation of antibody titers and diagnostic antibody cutoff values in patients with scrub typhus in South Korea

Table 3 Antibody titers in patients who had recovered from scrub typhus (N = 91) based on positive rates of the total antibody titer, as determined by the IFA used by company A

IFA of A Company	1 year	2 years	3 years	4 years	5 years	6 years	7 years	8 years	9 years	10 years	11 years	12 years	13 years
IFA of A Company	n (CP)	n (CP)	n (CP)	n (CP	n (CP)	n (CP)	n (CP)	n (CP	n (CP)	n (CP)	n (CP)	n (CP)	n (CP)
0	6 (100)	0 (100)	2 (100)	1 (100)	1 (100)	1 (100)	1 (100)	1 (100)	1 (100)	1 (100)	3 (100)	2 (100)	1 (100)
1:40	3 (62.5)	0 (100)	8 (88.9)	0 (66.7)	1 (85.7)	4 (87.5)	2 (80)	1 (66.7)	4 (83.3)	1 (83.3)	0 (50)	0 (0)	2 (66.7)
1:80	1 (43.8)	0 (100)	1 (44.4)	0 (66.7)	3 (71.4)	0 (37.5)	1 (40)	1 (33.3)	0 (16.6)	1 (66.7)	3 (50)	0 (0)	0 (0)
1:160	1 (37.5)	2 (100)	4 (38.9)	1 (66.7)	2 (28.6)	3 (37.5)	1 (20)	0 (0)	0 (16.6)	3 (50.0)	0 (0)	0 (0)	0 (0)
1:320	2 (31.3)	2 (75.0)	0 (16.7)	1 (33.3)	0 (0)	0 (0)	0 (0)	0 (0)	0 (16.6)	0 (0)	0 (0)	0 (0)	0 (0)
1:640	2 (18.8)	4 (50.0)	3 (16.7)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (16.6)	0 (0)	0 (0)	0 (0)	0 (0)
1:1280	1 (6.3)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (16.6)	0 (0)	0 (0)	0 (0)	0 (0)
1:2560	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (16.6)	0 (0)	0 (0)	0 (0)	0 (0)
1:5120	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	1 (16.6)	0 (0)	0 (0)	0 (0)	0 (0)
> 1:5120	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0(0)
Total n	16	8	18	3	7	8	5	3	6	6	6	2	3

Bold indicates the results obtained at cutoff values of ≥1:40 for total Ig detection, which are reference cutoff values for positivity
CP Cumulative percentage, IFA Immunofluorescence assay

ISSN: 1471-2334