Thereafter, kidneys retain or reabsorb the filtered proteins and return them to the circulating blood while removing wastes by excreting them in the urine. Whenever the kidney is compromised, their ability to filter the blood by differentiating protein from the waste, or retaining the filtered protein then returning which back to the body, is damaged. As a result, there is a significant amount of protein to be discharged along with waste in the urine that makes the concentration of proteins in urine high enough to be detected by medical machine.Medical testing equipment has improved over time, and as a result tests are better able to detect smaller quantities of protein. Protein in urine is considered normal as long as the value remains within the normal reference range. Variation exists between healthy patients, and it is generally considered harmless for the kidney to fail to retain a few proteins in the blood, letting those protein discharge from the body through urine. Albumin and immunoglobins
Albumin is a protein produced by the liver which makes up roughly 50%-60% of the proteins in the blood while the other 40%-50% are proteins other than albumin, such as immunoglobins.
The 2005 UK Chronic Kidney Disease guidelines state that protein/creatinine ratio is a better test than 24-hour urinary protein measurement. Proteinuria is defined as a protein/creatinine ratio greater than 45 mg/mmol (which is equivalent to albumin/creatinine ratio of greater than 30 mg/mmol or approximately 300 mg/g) with very high levels of proteinuria having a ratio greater than 100 mg/mmol.Protein dipstick measurements should not be confused with the amount of protein detected on a test for microalbuminuria which denotes values for protein for urine in mg/day versus urine protein dipstick values which denote values for protein in mg/dL. That is, there is a basal level of proteinuria that can occur below 30 mg/day which is considered non-pathology. Values between 30 and 300 mg/day are termed microalbuminuria which is considered pathologic. Urine protein lab values for microalbumin of >30 mg/day correspond to a detection level within the "trace" to "1+" range of a urine dipstick protein assay. Therefore, positive indication of any protein detected on a urine dipstick assay obviates any need to perform a urine microalbumin test as the upper limit for microalbuminuria has already been exceeded. Analysis
It is possible to analyze urine samples in determining albumin, hemoglobin and myoglobin with an optimized MEKC method. Treatment
Treating proteinuria mainly needs proper diagnosis of the cause. The most common cause is diabetic nephropathy; in this case, proper glycemic control may slow the progression. Medical management consists of angiotensin converting enzyme (ACE) inhibitors, which are typically first-line therapy for proteinuria.