Reading a system vairable from a blf file in Matlab

Question

I have a dbc file and a blf file. There is a system variable stored in the blf file which I would like to read. But using canDatabase() and blfread() function, I can only read the CAN signals and not system variables. Is there a separate function to read system variables from a blf file in Matlab. The system variable is also defined in the canDatabase. This is the code I use and I could not find any other function.

candb = canDatabase("dbcfilepathname");
blf_mydata = blfread("blffilepathname",1,"Database",candb);
signaltimetable1 = canSignalTimetable(blfdbc, "CAN_Main_var_1");