Haematocrit protocol - (May/05/2013 )

Hi, I am required to set up Teaching lab for High school students wherein I need to give them Blood samples for Haematocrit experiment. I have made a protocol myself by gathering info from net- First make up an Anticoagulant- make 0.5M EDTA (K salt)- 186.1g of EDTA to 800ml of MilliQ water- Adjust PH to 8 with NaOH (it takes ~20g), then bring volume to 1L and then autoclave. 1ml of this will contain186mg of EDTA. I picked up from the net, for 1ml of Blood ~1.8mg of EDTA is required. To get 1.8mg, I will take 9.8ul of EDTA solution for 1ml of Blood OR 980ul of EDTA for 100ml of Blood. Is this proportion right? I will be collecting Bovine blood one day before the lab. I will then wash with 0.9% Saline (NaCl). I will be using this washed blood for next 2 days for the lab. The washed blood will be stored in the fridge. Is this right? Sorry, for long question, but I would like to get confirmation from Bioforum. Many thanks in advance for the help.

I can't comment on the blood bit, but your protocol looks correct for preparing EDTA, though the K salts have a molar mass of 404.43 - s to get 1 L of 0.5 mol/L you need 202 g.

You could also make a more dilute solution to make measuring easier.

Many thanks bob1 for prompt reply. Is that ok if I store 'washed blood' in the fridge for 2 days, I mean will it work Ok for Haematocrit? How long it is stable in the fridge for this type of experiment? thanks again