Mr. John Gleeson:

Laboratories examine 30,000, 40,000, 50,000 or 100,000 samples per annum. Three false negatives might emerge three years later when we go back and look at them. Meanwhile, we are monitoring the period in question, and the positive predictive value is correct for their quarterly measure. It is complex. We are monitoring all the time. The false negative rate can only be determined against what, all the other positives? There could be 70,000 negatives, and three that might be false negatives when one looks back three years later under review conditions. It is minuscule.