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Interesting. It is amazing what wacky results one can get from contamination, creative dilution with iv fluids and such. In my "spare time!" I contribute to the Chemistry component of our local BMS degree. We have just introduced a new lecture looking at non disease causes for odd results. There are more cases than we might think. It is a valuable skill in lateral thinking to spot them Ian Hembling Ipswich ________________________________ From: Clinical biochemistry discussion list on behalf of Mohammad Al-Jubouri Sent: Wed 06/02/2008 09:34 To: [log in to unmask] Subject: Re: Severe hypernatraemia I am glad that few of our colleagues were so vigilant that they didn't believe the serum sodium despite it being analytically correct. There are two clues in this case; first you wouldn't expect a patient with such high serum sodium to be relatively fit & well (at least some mental clouding) and second the serum urea & creatinine don't show any degree of dehydration that you would expect with such severe hypernatraemia ( estimated pure water deficit of 11 litres!!). The only plausible explanation would be contamination, henec we performed the follwing additional tests: Chloride - 73 mmol/L Bicarb - 17.0 mmol/L Adj Calcium - 1.70 mmol/L Magnesium - 0.52 mmol/L Contamination with sodium salts (other than NaCl) from Na2-EDT or Na-citarate tubes, is the working theory. I couldn't track the community phlebotomist who took the sample, but when I phoned the GP, he was shocked to hear about the grossly high sodium as the patient was clinically well. I reassured him that contamination of the sample is the reason and suggested a repeat. Learning point: Be vigilant about pre-analytical errors and always relate the abnormal result to other surrogate results and of course the clinical presentation prior to clinical authorisation. Best wishes Mohammad ----- Original Message ---- From: Mohammad Al-Jubouri <[log in to unmask]> To: [log in to unmask] Sent: Tuesday, 5 February, 2008 4:16:00 PM Subject: Severe hypernatraemia For the sake of "learning clinical biochemistry" from our daily routine, may I present you with this case for interpreation: An elderly lady, relatively fit and well, had the following routine UEs requested by her GP: Sodium + 184 mmol/L Potassium - 3.4 mmol/L Urea 4.9 mmol/L Creatinine 78 umol/L eGFR 75 mL/min/1.73 m2 All results were double checked and are analytically correct. What advice would you offer her GP? regards Mohammad Dr. M A Al-Jubouri Consultant Chemical Pathologist ________________________________ Support the World Aids Awareness campaign this month with Yahoo! for Good <http://us.rd.yahoo.com/mailuk/taglines/isp/control/*http://us.rd.yahoo.com/evt=51947/*http://uk.promotions.yahoo.com/forgood/> ------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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