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Dear Rita, Don't you think it is about time that the profession stopped using these population based algorithms for individual patients? In addition to the innate uncertainty of measuring the ingoing quantities the uncertainty of the algorithm should be considered -as you rightly point out. Furthermore, it is theoretically impossible to go from an average (the algorithm can be viewed as a kind of average) to an individual. You face the same problem as with the eGFR! Cheerio, Anders Kallner -----Original Message----- From: Clinical biochemistry discussion list [mailto:[log in to unmask]] On Behalf Of Rita Horvath Sent: den 18 juni 2013 02:46 To: [log in to unmask] Subject: should we harmonise Ca adjustment formulas first? David, I do not know the answer to your question but instead I have another question - in fact I asked this from mail base members months ago but received no meaningful answers that I could have summed up. This relates to the adjusted Ca formula: is there any harmonisation achieved on which formula to use for both BCG and BCP albumin methods? In-house formulas (that we also use in my lab for BCP albumin) all suffer from the lack of proper validation and they are dependent on population Ca and albumin data (e.g. my lab mostly serves hospital population and a lot of kids and it is hard to validate our formula e.g. by comparing adjusted Ca to ionized Ca data as the latter test is usually done in critically ill or in those who need blood gas measurements for various acute reasons). So before Pathology Harmony suggests that we shall all use adjusted Ca should we not work on harmonising the Ca adjustment formulas for the various albumin methods? I am sure there is a lot of variation out there...I am also certain that clinicians, using labs which do not provide adjusted Ca results, simply use the old and simple adjustment formula of Ca+0.02(40-albumin) which is accessible from the web or which allows simple calculations by head. Surely this is not applicable to BCP albumin. So may I repeatedly ask mail base members of 1/ what Ca adjustment formula your lab is using? 2/ for which albumin method? 3/ and for which Ca method? 4/ Are there any exclusion criteria when the use of the adjustment formula is limited, 5/ and if so what comments do you put on lab reports? Kind regards, Rita Prof. Andrea Rita Horvath, MD, PhD, EurClinChem, FRCPath, FRCPA Past President of the European Federation of Clinical Chemistry and Laboratory Medicine Clinical Director, SEALS North, Department of Clinical Chemistry Level 4, Campus Centre, Prince of Wales Hospital Barker Street, Randwick, NSW 2031, Sydney, Australia Tel: (+612)-9382 9078 Fax: (+612)-9382 9099 Mobile No: (+61)-404 027 843 -----Original Message----- From: Clinical biochemistry discussion list [mailto:[log in to unmask]] On Behalf Of David Wright Sent: Tuesday, 18 June 2013 1:09 AM To: [log in to unmask] Subject: Calcium Creatinine Clearance Ratio, CCCR Calcium Creatinine Clearance Ratio is used in the diagnosis of FHH. Currently setting up parameters on the Host computer to make CCCR available. A question to ponder.... Formula (e.g. Hammersmith) appear to use Serum Calcium and not Adjusted Calcium (Pathology Harmonization) in CCCR calculations. Does using Adj Ca make a significant difference? Does using Adj Ca introduce more error into the calculation (various formulae for Adj Ca) or reduce a potential error (low or elevated albumin levels). Thanks David Wright Lead BMS. Antrim ------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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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 Green Laboratories Work http://www.laboratorymedicine.nhs.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/