A normal glomerular filtration rate does not exclude urinary protein. There can be a situation where there is urinary protein but glomerular filtration rate is normal.
In the early stage of many kidney diseases, the main manifestations are urine protein, urine occult blood, edema, hypertension, etc., while glomerular filtration rate is normal. With the progression of nephropathy, the glomerular filtration rate decreases gradually. Even some nephropathies, especially interstitial nephritis, may progress to uremic stage and still have no urinary protein, or only a small amount of urinary protein.
However, urine protein and glomerular filtration rate are not completely unrelated, a large amount of urine protein will promote the progression of nephropathy, resulting in the decline of glomerular filtration rate, the larger the quantitative amount of urine protein, the faster the glomerular filtration rate decline.
In order to clarify whether there is urine protein, you need to do routine urine, if it is a small amount of urine protein, you may need to do urine microalbumin creatinine ratio or 24-hour urine protein quantification. If there is an abnormality, timely hospitalization is required for symptomatic treatment.