Hi, as the members said that there is no LSL for the TAT, one thing i would like to share with u all is that, the process for investigations take 2hr for normal reports and if there is any abnormal results the test is repeated and so the TAT will increase. So here in this case can i take USL as 4 hours and LSL as 2 hours. Pls suggest me. Thanking you all Vishwanath