Composite testing for ante-mortem diagnosis of Johne’s disease in farmed New Zealand deer: correlations between bacteriological culture, histopathology, serological reactivity and faecal shedding as determined by quantitative PCR

Table 1 Sensitivity and specificity values for qPCR calculated using HEYM culture as a gold standard

	Shedding threshold for qPCR test positivity (organisms/g)
	10 ^-1	10 ¹	10 ²	10 ³	10 ⁴	10 ⁵	10 ⁶
Sens.	0.91	0.91	0.91	0.85	0.68	0.52	0.37
Spec.	0.73	0.73	0.83	0.89	1.00	1.00	1.00
PPV	0.91	0.91	0.94	0.95	1.00	1.00	1.00
NPV	0.74	0.74	0.75	0.66	0.52	0.42	0.35

Sensitivity and specificity values for qPCR calculated for different shedding states using HEY solid medium as a gold standard based on NVSL proficiency panel culture results.

ISSN: 1746-6148