Analyze the indeterminate test results(ITRs) distribution in the detection of Quanti-FERON-TB Gold In-Tube (QFT-GIT), a kind of interferon gamma release test, within patients suspected with tuberculosis infection.

Four thousand eight hundred and fifty-four blood samples from patients speculated with tuberculosis infection were collected from 104 hospitals in different regions of Shandong province from January 2015 to June 2016, all samples were detected with QFT-GIT in Ji′nan Jinyu medical examination center. A retrospective study was performed to analyze the incidence and distribution of ITR in gender, ages and levels of hospitals, and to explore the causes of ITRS by reviewing the data in a comprehensive way.

QFT-GIT was used to detect 4854 cases of suspected tuberculosis infection. The incidence of ITRs was 6.55% (318/4854) in all blood samples, including: 24.53% (13/53) in first grade hospital, 6.25% (52/832) in second grade hospitals and 6.37% (253/3969) in the third grade hospitals. There was a significant difference in the incidence of ITRs between the first and two grade hospitals and the level three hospitals, compared with the level of(χ² were respectively 24.462, 27.908, P<0.001). There was no significant difference in the incidence of ITRs between the two hospitals and the grade three hospitals(χ²=0.018, P>0.05). the incidence of ITR was 6.09% (117/1921) in female was, and 6.85%(201/2933) in male, which showed no significant difference (χ²=2.135, P>0.05). More than 76 years old was the highest incidence of ITRS[9.39% (63/671)], and the 16-30 years group[3.43%(23/670)], 31-45 years group[5.91%(46/779)], 46-60 years group [6.13%(75/1124)]differences were statistically significant (χ² were 19.816, 6.294, 6.828; and P=0.001, 0.012, 0.009). There was significant difference between 6-15 years old group [7.89%(9/114)]and 16-30 years old group (χ²=4.954, P<0.05), there was significant difference between 16-30 years old group and 61-75 years old group[7.24%(98/1353), χ²=11.569, P<0.001]. Eighty-three from 194 cases of ITR could be attribute to the use of large dose of immunosuppressant drugs and predison (36) accounting for 43.37%, severe inflammation (22), accounting for 26.50%, and in, revealing that the clinical detection of this project causes the occurrence of ITRs, immunosuppressive drugs, lymphocyte is abnormal and inflammatory diseases are the dominant factors lead to this result.

The difference in patients infected with MTB ITRs QFT-GIT to detect suspicious tuberculosis infection in a hospital and two hospital three hospitals may be different with different level of hospital patients with different diseases, treatment status, level three the main reason for immunosuppression and hormone drugs, two hospitals that low level lymphocytes mainly caused by hospital not likely to determine the cause of serious inflammation, may also by different levels of hospital quality control analysis of the influence of different degree of specimen. The incidence of ITRs in different gender groups there were no differences. In the age group over 76 years, ITRs group was the highest, and the 6-15 years old group, 61-75 years group, 46-60 years group, 31-45 years group, 16-30 years group. There was significant difference between and 16-30 years old group, and age factor was an important factor of ITRs.