Hi Sharon, We have exactly the same problem with our blood gas EQA samples. I contacted Radiometer and they said that because it is a clear solution it won't have a tHb which is needed for the analyser to calculate standard bicarbonate. The thing is sometimes we do get a standard bicarb result and sometimes not. Kind Regards, Dorinda O’Neill Point of Care Biomedical Scientist Point of Care Testing Biochemistry Laboratory Craigavon Area Hospital Southern Health And Social Care Trust Phone: 02838360651