Brief Answer:
Microscopic hematuria

Detailed Answer:
Hello XXXXXXX

Microscopic hematuria can be from anything that causes inflammation in the genitourinary system. It can sometimes also be from muscle breakdown after physical exertion and sometimes runners have this happen and it isn't clear why. But the bleeding from exertion or running generally isn't concerning.

Now about bleeding from inflammation. Some of the things that can cause this are infection (urinary tract infection) or prostatitis, but usually people have some symptoms that go along with this.

Stones or smaller "gravel" anywhere in the tract can cause irritation that results in bleeding too.

Autoimmune problems and vascular deformities in the kidneys can too.

But the most concerning thing is the possibility of malignancy along the urinary tract. This is relatively rare compared with the other causes, but must be ruled out and not ignored.

Given that your results were available so quickly, unless your exam was done in a place that has a large lab, most likely what was read was a "dipstick urine" test with a paper dip stick that changes colors given the presence of sugar, protein, blood, bacteria, and other things. This is a quick analysis but doesn't provide detail. You can get more information by sending the urine to a lab for a full urinalysis. The pathologist in the lab can look to see what abnormalities there might be that can give a clue as to the cause of the bleeding. Also, if there is any indication of bacteria or you are having any urinary tract symptoms, a culture should be done as well to look for possible infection.

Unless there is an obvious cause for the microscopic hematuria such as infection or vigorous exercising, the protocol we use in the US is to repeat a urine specimen in 6 weeks. I am not sure the reason for repeating this in a few days but perhaps there are different protocols used in the UK.

I am attaching an article on the assessment of asymptomatic microscopic hematuria in case you are interested in reading more on the evaluation of this. It won't "link" blue here, so if you want to read it, you will have to copy and paste the link into your search bar.

Here it is:
http://www.aafp.org/afp/2013/1201/p747.html

To ease your mind I can say the majority of the time, this is due to a benign process.

I hope this information helps.

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