I'm not sure if it can be a side effect or not, but it could be a kidney infection. Consult your health care provider.
If Your A Woman It Could Be Your Period And A Crap Or Urine Infection
The knot of blood vessels is called the glomerulus. This filters the fluid that will become urine. It will keep much of the water back.
moves water from the urine back into the blood
Kidney infection. Painful urination, cloudy urine, pain around waistline, blood in urine. Definitely a kidney infection.
A tiny structure that removes wastes from the blood and produces urine is the kidney. Humans have two kidneys located, one on each side, in the lower back.
It clears the impure blood
I would believe the blood test. Discuss the matter with your doctor.
two bean-shaped excretory organs that filter wastes (especially urea) from the blood and excrete them and water in urine; "urine passes
Blood contains glucose because it is an essential energy source for cells in the body. However, the kidneys normally filter out glucose from the blood and reabsorb it back into the bloodstream, so that there is no glucose present in normal urine. The presence of glucose in urine, known as glucosuria, can be a sign of diabetes or other health conditions.
Antidiuretic hormone (ADH) helps regulate water balance in the blood by increasing the permeability of the kidneys to water, allowing them to reabsorb more water back into the bloodstream. This helps in conserving water and concentrating the urine, ultimately reducing the amount of water lost in urine and maintaining blood volume and pressure within a narrow range.
The concentration of amino acids and glucose is typically higher in blood than in urine. In healthy individuals, the kidneys filter these substances from the blood, reabsorbing most of the amino acids and glucose back into the bloodstream. Consequently, only trace amounts of these nutrients are usually found in urine. Elevated levels in urine can indicate certain health conditions, such as diabetes or kidney dysfunction.
if your sure the blood is from your urine, it could be a kidney stone trying to pass through which i hear is very painfull for most. Especially if the back pain is on one side of your back.