Table 1. Diagnostic performance of five diagnostic procedures used to differentiate between LDA positive or negative cattle identified with left-sided “ping” sounds.

Diagnostic test	True +ve	False +ve	True −ve	False −ve	Sensitivity(%)	Specificity(%)	PPV(%)	NPV(%)	Diagnostic accuracy(%)
USG over the area of “ping”	23	9	3	0	100	25	71.88	100	74.3
USG over the ventral abdominal wall	23	2	10	0	100	83.33	92	100	94.3
Rectal findings	19	3	9	4	82.6	75	86.36	69.23	80
pH value of 2–4 of aspirated fluid	23	1	11	0	100	91.67	95.83	100	97.14
Milk BHBA of 100 μmol/l	20	2	10	3	86.96	83.33	90.9	76.92	85.71

The figures are presented in numbers (true +ve, false +ve, true −ve, and false −ve) and in percentages (sensitivity, specificity, PPV, NPV, diagnostic accuracy).

PPV = positive predictive value; NPP = negative predictive value.