Percent sensitivity, specificity, accuracy, predictive values and likelihood ratios
After calculating the percent sensitivity, specificity, accuracy, predictive values and likelihood ratios for all the significantly altered parameters, ALP followed by Zn was most in agreement with IDF criteria for SCM considered irrespective of the causative agents (Tables 4 and 5).
The likelihood ratios for ALP and Zn were 16.54 and 12.52 respectively. In the case of Fe, Co and LDH apart from percent specificity and negative predictive value all the other values were found to be too low to be useful in predicting SCM caused by Gram negative bacteria (Table 4), but there values were satisfactory and acceptable when we measured them in SCM milk infected by Gram positive bacteria only (Table 5).
When both ALP and Zn was considered together to diagnose SCM, the values were
greater than 99% for all kinds of infections. The likelihood
ration was also very high (Table 4).