Stratified Threshold Values of QuantiFERON Assay for Diagnosing Tuberculosis Infection in Immunocompromised Populations

Table 2

Regression coefficients and associated statistics.

Predictors	Coefficient	SE	t	P	95% CI
					Lower	Upper
Age (y)	−0.0030	0.0027	−1.12	.26	−0.0083	0.0023
background (IU/mL)	0.57	0.089	6.46	<.0005	0.40	0.75
Mitogen background (IU/mL)	0.016	0.0056	2.78	.006	0.0046	0.027
Albumin (g/dL)	0.0055	0.11	0.05	.96	−0.21	0.22
Hemoglobin (g/dL)	−0.023	0.029	−0.79	.43	−0.080	0.034
Neutrophil (1000/mm^3)	−0.14	0.021	−6.51	<.0005	−0.18	−0.095
Monocyte (1000/mm^3)	0.26	0.23	1.13	.26	−0.19	0.72
Lymphocyte (1000/mm^3)	0.61	0.13	4.65	<.0005	0.35	0.87
Eosinophil (1000/mm^3)	−0.63	0.44	−1.43	.15	−1.5	0.23
CRP (mg/dL)	−0.015	0.012	−1.27	.21	−0.038	0.0081
AST (IU/L)	−0.0023	0.0030	−0.76	.45	−0.0082	0.0036
ALT (IU/L)	0.0047	0.0032	1.48	.14	−0.0015	0.011
Creatinine (mg/dL)	0.18	0.12	1.48	.14	−0.058	0.41
Mitogen×Lymphocyte	−0.0073	0.0034	−2.16	.031	−0.014	−0.00067
Intercept (ln IU/mL)	0.22	0.47

Note. Regression coefficients for linear regression of log-transformed antigen-stimulated IFN-γ production by the QuantiFERON-TB Gold. Wald (t) test statistics are based upon 698 degrees of freedom. 𝑃 values are not adjusted for multiplicity. Diagnostic plots do not indicate significant departures from normality for the distribution of residuals or nonlinearity in the predictions. The maximum variance inflation factor (<4) is within an acceptable range. CRP: C-reactive protein; AST: aspartate amino transferase; ALT: alanine aminotransferase; SE: standard error; CI: confidence inter.