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Actually, googling "microscopic hematuria" brings up an American Urological Assn guide, a Mayo Clinic guide, and a Cleveland Clinic guide. And also a Canadian algorithm. Looks like they are pretty similar except in the number of samples required, and that there are lots of false positives.
Interestingly, over here, the finding is usually reported as "rbc's per high power field", and can be on either an unspun or spun specimen.
Our local guidelines (NHS in Scotland) suggest three separate confirmed episodes of microscopic haematuria on either dipstick or msu; with menstrual loss, infection, prostatism, or calculus ruled out/not expected.
In an earlier life as a GP I took anything above 20 rbc/millionth of a litre as significant, but the normal values seem to vary from lab to lab.
1 plus on the urine dipstick I use is, according to the chart, equivent to >10 rbc /millionth of a litre. So it would be logical to take anything above 10 as eqivalent to a positive dipstick for blood.
It is a bit tick box I know. (and how you convert rbc/millionth of a litre to rbc/HPF (high power field), has always been a mystery to me.
and how you convert rbc/millionth of a litre to rbc/HPF (high power field), has always been a mystery to me.
Me too. It has always been a mystery how the two most established medical systems in the English speaking world manage to come up with different standards of measurement in almost every aspect of medicine. It's like they purposely diverge (which I suppose is as it is in most other topics also!).
Thanks for the info, I spoke to our man at the lab, who suggested that the readings from his automated machine have to be read in context of what the machine is designed for (detecting UTI's).
He reckoned that the (?British) Urological Society say two readings of 1+ on a dipstick is used to define microscopic haematuria. I think the referral pathway then depends on whether the blood U+E's are deranged.
unless you've had a stone or recent UTI I strongly recommened letting your GP know. Microscopic haematuria could mean other things - might need a camera look inside your bladder but ask for a medical opinion.
So as a urologist, my brief guide would be this. The dipstick does throw up a number of false positive results, and ,as a chemical reagent test, is inferior to the direct urine lab microscopy (" MSU MC & S).
On most labs, < 10 RBC would be normal. An example is pasted below : Urine pH 7 Protein Nil Glucose Nil Blood Nil Ketones Nil Bilirubin Nil Specific gravity 1.016 (1.005 - 1.030)