LH stand for lutenizing hormone. We have certain hormone called as follicle stimulating hormone and luteinising hormone which have certain peaks and downs as they go in and cause ovulation in a body system. LH in a normal body system is something between 5 to 20 milli international units per ml. 24 to 36 hours just prior to ovulation there is a surge in the LH and that rises upto 25 to 40 milli international units per ml. Every time doing a blood test might not be feasible. There are simple tests which are available and the urine sample itself can be checked just like a pregnancy card test. LH surge cards are also available these day and if somebody is not able to go in for their ovulation studies or would like to try out their natural cycle, whether the ovulations going to happen in that period or not. It is a very good tool kit to be used and one could know whether the two lines are coming positive that LH levels are adequate enough. So basically the testing for the lutenizing hormones is done for this purpose to check whether the ovulation has happened, is rather going to happen or within the next 24 to 36 hours.