When the nephrons are damaged, protein / Albumin leaks in the urine. More than 80% of kidney diseases can be
detected by estimating the urinary protein loss. It is also possible to estimate the kidney function by calculating
Glomeruar Filtration Rate (GFR). This is done by estimating the serum Creatinine and using standard formulae.
Unfortunately this could be unreliable since serum Creatinine estimations are not standardised uniformly in all the
laboratories.
How to detect urinary Protein?
The simplest way is to use a strip and dip it in urine. The albumin / protein loss is semi quantitated by seeing the
colour change as Trace, 1+, 2+, 3+. (As shown in photos) below)
Estimation of a spot sample of urine for protein and Creatinine. The normal ratio is less than 0.2 (<0.2).
Estimation of urinary micro Albumin. The normal value of urine Albumin is 30 mg per day. Between 30 to 300mg per
day is Microalbuminuria and greater than 300 mg per day is called Macro Albuminuria.
This can also be correlated with urinary Creatinine estimation.
Normal values for Albumin / Creatinine Ratio is < 17 mg / gram in males and in females < 25 mg / gram
24 hours urinary protein estimation - This is the gold standard of estimations. Normal excretion should be less than 150 mg per day.
In developing countries or villages it is possible to check for urine protein by heat test after adding Sulfosalicylic acid to
the urine.
Other basic tests to detect kidney disease
Blood Urea and Serum Creatinine estimations
This is a blood test which can be done without fasting. The normal blood Urea level varies from 20 to 50 mg %. The normal serum Creatinine values range from 0.6 to 1 mg %. The values should be interpreted together and according to the laboratory reference range. It is possible to estimate the percentage of kidney function from serum Creatinine using certain formulae.
Ultrasound imaging of the kidneys.
This is a very simple non-invasive investigation which can tell the size of the kidneys and look for any blockage, tumor or stones in the kidneys. Caution is advised while interpreting very small stones by ultrasound.
