In poln of 1000 attending Dm clinic,100 were tested with Gtt were positive,140 tested with FBS,and 98 were positive, calculate specificity, sensitivity, negative and positive predictive value of FBS?

To calculate the specificity, sensitivity, negative predictive value, and positive predictive value of FBS (Fasting Blood Sugar) test, we need the following information:

True Positive (TP) = 98 (number of people who tested positive with FBS)
False Positive (FP) = 140 - 98 = 42 (number of people who tested negative with FBS but were actually positive)
True Negative (TN) = 1000 - 140 - 42 = 818 (number of people who tested negative with FBS and were actually negative)
False Negative (FN) = 100 - 98 = 2 (number of people who tested positive with FBS but were actually negative)

Now we can calculate the required values:

Specificity = TN / (TN + FP) = 818 / (818 + 42) = 818 / 860 ≈ 0.9535 or 95.35%

Sensitivity = TP / (TP + FN) = 98 / (98 + 2) = 98 / 100 = 0.98 or 98%

Negative Predictive Value (NPV) = TN / (TN + FN) = 818 / (818 + 2) = 818 / 820 ≈ 0.9988 or 99.88%

Positive Predictive Value (PPV) = TP / (TP + FP) = 98 / (98 + 42) = 98 / 140 ≈ 0.7 or 70%