Glomerular range proteinuria differentiated by non glomerular protein urea by -
Urinary dipstick testing is a valuable screening tool for the detection of proteinuria; it is only semi-quantitative, however, as it is highly dependent on the concentration of the urine. Typically, standard dipsticks test positive for protein once the urinary protein exceeds approximately 0.5 g/24 hrs , trace to 1+ on dipstick may be observed in very concentrated urine from individuals with no evidence of renal pathology. Hence all patients with persistent proteinuria on dipstick should have the amount of protein quantified to guide fuher investigations (Fig. 15.10). When more than 1 g of protein per day is being excreted, glomerular disease is likely and this is an indication for renal biopsy. Since quantification by 24-hour urine collection is often inaccurate, the protein:creatinine ratio (PCR) in a spot sample of urine ispreferred. This makes an allowance for the variable degree of urinary dilution and can be used to extrapolate to 24-hour values . Changes in PCR also give valuable information about the progression of renal disease and response to therapy in CKD. It is possible to measure albumin:creatinine ratio (ACR), but this requires a more expensive immunoassay and is usually reserved for situations when high sensitivity is required, such as detection of the early stages of diabetic nephropathy . It is sometimes helpful to identify the type of protein in the urine. Large amounts of low-molecular-weight proteins, such as b2-microglobulin (molecular weight 12 kDa), in the urine suggest renal tubular damage and are referred to as tubular proteinuria. This rarely exceeds 1.5-2 g/24 hrs (maximum PCR 150-200 mg/ mmol; for conversion of mg/mmol to mg/dL). Free immunoglobulin light chains (molecular weight 25 kDa) are filtered freely at the glomerulus but are poorly identified by Ref Harrison20th edition pg 394
Proteinuria> 3.0 - 3.5 g/day
Globulin > albumin
Albumin to B2 microglobulin ratio 100:1
TammHarsfall protein
Kidney