So for Lactate Acid testing, I have talked to my Mum, and she is going to do some looking around. But off the top of her head I believe she recommend this company for self testinghttp://www.lactate.com/
It is a little pricey but if you go in with a few people it becomes cheaper. This was the competitor to the test she developed. Unfortunately for you, after my mum sold her company the people who bought never really brought it to market.
I will post any other information that she tells me.