Interpreting MSU results.

[gingernut]

Anyone have an "idiot's" guide, in particular when (what level) to investigate the prescence of red blood cells on microscopy ? (Reported in numbers of rbc's x10 to the power of 3 per ml).

Cheers, ginge.:)

[obgraham]

Male, or female?

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.

[gingernut]

thanks graham, I'm trying to work out when the patient has "microscopic haematuria." (in terms of needing to refer.)

[kui2324]

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.

[Phororhacos]

CAA have a guideline..

see http://www.caa.co.uk/docs/2499/Abnormal%20Urinalysis%20FC.pdf

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.

[obgraham]

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!).

[gingernut]

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.

Watch this space, am on the job :)

[Phororhacos]

The brand of strips I used today indicated trace was equivalent to 10rbcs and 1+ equivalent to 25rbcs (per millionth of a litre).

[cc86]

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.

[gingernut]

Thanks cc, trouble is, I'm meant to be the expert:p

[cc86]

lol fair enough! what did you decide to do in the end? did you find an answer?

[gingernut]

Yep, ignore the MSU result, and rely instead on the dipstick to diagnose haematuria.:)

[aussiepax]

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)

Microscopy
Leucocytes 3 x10^6/L ( <10 )
RBC Erythrocytes 3 x10^6/L ( <10 )
Epithelial cells 0 x10^6/L
Casts NIL

Culture No growth

Thus I rely on that, and urine cytology and ultrasound, to then decide who needs cystoscopy.

(Take also in context of AUA , EAU and BAUS guidelines).

Cheers,
Graham.

[gingernut]

Thanks Graham, appreciate the advice, it does seem to be at odds with the Brits...

http://www.baus.org.uk/Resources/BAUS/Documents/PDF%20Documents/BAUS%20in%20general/haematuria_consensus_guidelines_July_2008.pdf

? Maybe because of the role of primary care in initial detection.

[obgraham]

Aussiepax:
Is that microscopy report based on a machine-read cell count, or a manual look-see by the tech?

(My standard advice is to always follow the recommendation of any doc named Graham.)

Graham 1 of 2

[gingernut]

Is that microscopy report based on a machine-read cell count, or a manual look-see by the tech?

My eldest cousin is called Graham, and he's a lovely lad. He's a bit grey haired now.

Here's my position, I see about 50 patient's a day, and for various reason's, I send 3 or 4 MSU's a day to the lab.

My 6 other colleagues probably do the same.

When do we refer, and when do we not ?

[Flyin'Dutch']

You should have local guidelines, developed with your pathlab and urologists.

Persistent haematuria (as defined by your local clinicians and lab) in conjunction with national guidelines should be investigated.

[gingernut]

thanks for that.

[aussiepax]

that would be a machine count for routine ones.