Overview
Urine chemical examination part two focuses mainly on the detection and evaluation of proteins and glucose in urine, which are key indicators of renal function and metabolic status. Normally, urine contains only trace amounts of protein and glucose that are not detectable by routine methods. Proteinuria refers to the presence of excess proteins in urine, with normal excretion being up to 150 mg per day. The proteins present may include albumin, globulins, and Tamm–Horsfall protein secreted by the ascending loop of Henle. Glycosuria refers to the presence of detectable glucose in urine and occurs when filtered glucose exceeds the renal tubular reabsorptive capacity. Chemical examination of proteins and glucose helps in diagnosing kidney diseases, diabetes mellitus, systemic disorders, and early renal damage.
Symptoms
Abnormal findings of protein and glucose in urine are often associated with symptoms of an underlying disease. Proteinuria may be linked with swelling of the face or legs, frothy urine, reduced urine output, or signs of chronic kidney disease. In many cases, especially in the early stages, proteinuria may be asymptomatic and detected only on routine testing. Glycosuria is commonly associated with symptoms such as excessive thirst, frequent urination, weight loss, fatigue, and blurred vision seen in diabetes mellitus. In severe cases, glycosuria may be accompanied by dehydration and ketosis.
Causes
Proteinuria is caused by a variety of renal, systemic, functional, and transient conditions. Renal causes include glomerular diseases such as nephrotic syndrome, glomerulonephritis, diabetic nephropathy, and tubular damage, including Fanconi syndrome. Systemic causes include diabetes mellitus, uncontrolled hypertension, and autoimmune disorders like lupus erythematosus. Functional and transient proteinuria may occur due to exercise, fever, orthostatic posture, pregnancy, or urinary tract infections. Glycosuria occurs when blood glucose levels exceed the renal threshold of approximately 180–200 mg/dl, most commonly due to diabetes mellitus. It may also occur due to reduced renal threshold, tubular dysfunction, pregnancy, or excessive glucose load.
Risk Factors
Risk factors for proteinuria include diabetes mellitus, hypertension, autoimmune diseases, chronic kidney disease, infections, pregnancy, and use of nephrotoxic medications such as NSAIDs and aminoglycosides. Elderly individuals may show proteinuria associated with occult malignancy. Risk factors for glycosuria include diabetes mellitus, stress, pregnancy, renal tubular disorders, and medications affecting glucose handling. Improper urine collection, contamination, and delayed testing may also influence test results.
Prevention
Prevention of abnormalities related to urine proteins and glucose relies on early screening, good disease control, and accurate testing practices. Tight glycemic control in diabetic patients helps prevent glycosuria and diabetic nephropathy. Management of hypertension, prompt treatment of infections, and avoidance of nephrotoxic drugs reduce the risk of proteinuria. Proper urine sample collection, confirmation of positive results by repeat testing, and use of appropriate qualitative and quantitative methods improve diagnostic accuracy. Regular monitoring in high-risk individuals allows early detection of renal and metabolic disorders and helps prevent long-term complications.
