I imagine that it was red cells otherwise they would have called in prescription for you if it was white cells..
Red blood cells (or any type of cells) in the urine should be investigated. The most common reason is a urinary tract infection- this may or may not be painful, but usually you have burning.
In hematuria, your kidneys - or other parts of your urinary tract - allow blood cells to leak into urine. A number of problems can cause this leakage, including:
As you can see, there are a number of causes, some of which are more concerning than others.
It is great that you are following up in Oct 30. This may have been just a transient event and you will not need a workup. But they are going to recheck your urine again to make sure that it is clear. If you still have the red blood cells, then they usually start off with a cystoscopy to check your bladder. In some cases they may do a CT or MRI of your abdomen to look at the kidneys for any tumors or abnormalities.
Hang in there.
If you have any fever, back pain, vomiting or other concerning symptoms, do not wait for you appointment, go to the ER>