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A somewhat dated but nice review of this subject can be found in Diabetic Medicine 1990 vol 7: 199-206 (Burrin and Alberti) entitled "What is blood glucose: Can it be measured" Mario D'Costa Ph.D. FCACB Director of Clinical Chemistry and Core Lab St. Joseph's Health Centre 30 The Queensway, Toronto On, Canada, M6R 1B5 Tel: 416-530-6263 Fax: 416-530-6559 email: [log in to unmask] >>> <[log in to unmask]> 05/08/02 04:45AM >>> Dear John, I agree with Andrew that you cannot assume that you are measuring plasma glucose. I think that you should look into the small print of the relevant instrument manual. Our Medisense glucose meter manual talks about "accurate blood glucose readings". Under the section "Calibration", it shows nice photographs showing "how to" calibrate. Our Precision G manual states that the accuracy was assessed by comparison with the YSI models 2300 Stat and Stat Plus analysers, with a correlation y=0.938(x) +0.59mmol/L, for "fresh whole blood". Our Abbott representative said that future Medisense manuals would more explicitly state what was being measured. I don't know whether blood gas instruments will try to mimic ward blood glucose meters or lab plasma glucose results. Regards Graham Ellis St. John's Hospital, Livingston, West Lothian > -----Original Message----- > From: Andrew Lyon [SMTP:[log in to unmask]] > Sent: 08 May 2002 03:23 > To: [log in to unmask] > Subject: Re: Glucose measurements in blood gas analysers - whole > blood or plasma? > > Theory may not always match reality and I do not think you can > assume that whole blood levels will always equal plasma results when > using electrodes for measurements. > > We have several ABL 725 analyzers and perform monthly > comparisons on a few samples to confirm agreement. (whole blood versus > plasma from those whole blood samples). The glucose results from the > ABL match the plasma glucose levels reliably, in our experience. (I > don't have data handy, but can forward comparison data at a later date). > The close match of the results is likely a result of electrode design > and the calibrators. > > On the other hand, glucose meters are (or were) notorious for > generating different results on whole blood and plasma and only recent > changes to the design of the test strips reduced the impact of > hematocrit on some meter models. There are a number of reports > published on the impact of hematocrit on electrolyte measurements by > ISE. It may be that glucose enzymatic-biosensors are less prone to > hematocrit effects that potentiometric electrodes, but I'm certain that > generalization can be made. Those are my thoughts...... Regards, Andrew > > Dr. Andrew W. Lyon > Univ. Calgary, Calgary, AB, Canada > > > > > > -----Original Message----- > From: clinical biochemistry discussion list > [mailto:[log in to unmask]] On Behalf Of John Whitfield > Sent: May 7, 2002 7:05 PM > To: [log in to unmask] > Subject: Glucose measurements in blood gas analysers - whole blood or > plasma? > > > I have been asked whether glucose results from our blood gas analyser > are equivalent to plasma glucose or whole blood glucose. This arose from > a discussion of whether we should quote a different reference range > depending on the method of analysis. > > My preliminary scientific answer is that the electrode is in contact > with the plasma phase of the whole blood and therefore the result given > is the plasma glucose (just as the potassium result is the plasma > potassium). > > On the less scientific and more practical side, one could say that since > no-one is going to run their GTTs through this kind of system, and > anyone who gets a blood gas sample analysed is pretty sick, a few > percent difference doesn't really matter anyway. > > The system in question is the Radiometer ABL 725, but the principle > should apply to any electrode-based system. Does anyone have a contrary > opinion, or data, so we don't have to do a comparison? > > thanks > > John Whitfield > Clinical Biochemistry > Royal Prince Alfred Hospital > Sydney, Australia > > > Phone (+61) 2 9515 5246 > Fax (+61) 2 9515 7931 > > Disclaimer: > This message is intended for the named addressee and may contain > confidential information. If you are not the intended recipient, please > disregard it. Views are those of the sender and not necessarily those of > Royal Prince Alfred Hospital or Central Sydney Area Health Service. > > ------ACB discussion List Information-------- > This is an open discussion list for the academic and clinical community > working in clinical biochemistry. Please note, archived messages are > public and can be viewed via the internet. Views expressed are those of > the individual and they are responsible for all message content. > > ACB Web Site > http://www.acb.org.uk > List Archives http://www.jiscmail.ac.uk/lists/ACB-CLIN-CHEM-GEN.html > List Instructions (How to leave etc.) http://www.jiscmail.ac.uk/ > > ------ACB discussion List Information-------- > This is an open discussion list for the academic and clinical > community working in clinical biochemistry. > Please note, archived messages are public and can be viewed > via the internet. Views expressed are those of the individual and > they are responsible for all message content. > > ACB Web Site > http://www.acb.org.uk > List Archives > http://www.jiscmail.ac.uk/lists/ACB-CLIN-CHEM-GEN.html > List Instructions (How to leave etc.) > http://www.jiscmail.ac.uk/ ------ACB discussion List Information-------- This is an open discussion list for the academic and clinical community working in clinical biochemistry. Please note, archived messages are public and can be viewed via the internet. Views expressed are those of the individual and they are responsible for all message content. ACB Web Site http://www.acb.org.uk List Archives http://www.jiscmail.ac.uk/lists/ACB-CLIN-CHEM-GEN.html List Instructions (How to leave etc.) http://www.jiscmail.ac.uk/ This email may contain privileged information which is only intended for the recipient(s). If you are not the intended recipient, please inform the sender via email-reply and permanently delete this email plus any attachment(s) associated with it. ------ACB discussion List Information-------- This is an open discussion list for the academic and clinical community working in clinical biochemistry. Please note, archived messages are public and can be viewed via the internet. Views expressed are those of the individual and they are responsible for all message content. 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