When medicine is stored in a warehouse or any storage facility, there might be temperature fluctuations. Assume that when you accept the goods, the temperature recorded till then was in perfect condition and you shifted to your storage. You might use a new data logger and commence recording. Few days or weeks later, you take the medicine for onward despatch. At this point, you first check whether the temperature has been always within the limits. You find that the temperature exceeded a few times beyond the limits. In such a case, you will check the MKT value to decide whether it is usable. If the MKT is within the limits, then medicine is assumed to be good for use.