Split The Data And Receive Back From The Box?

I am writing an automation program for an associated research HYPOT tester and one of my current problems is trying to split the data i recieve back from the box.Currently i have two commands i use TD? and SALL? both do the same thing but return different data. TD? when sent to the box will return the test results and of course there is no auto return when test is complete so i have to either set some kinda of timer to get the data after the test is complete or just keep pinging the box tell the test returns with either a pass or fail.my problem is when i ping the box with TD? it returns

"M11,ACW,test results{pass|fail},1.50,10.00,10ms"

What I am trying to do is use a split command to split that line into strings based off "," as my dilimeter. Currently i am useing this set up

dim resultstring as string = main.serialport1.readexisting
dimresultarray as string = split(resultstring, ",",6)
txtTestResult.Text = resultarray(2)

for the most part is does return the test results but other times it will either error out saying that resultarray(2) is out side the index or it will display one of the other strings (acw or 1.50).Is there a more accurate way to do this.I am also printing the full string pulled from the buffer into a text doc as a data log.