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Rat Urinary Protein Assay

The rat urinary protein assay kit uses the turbidity method in a 96-well flat bottom plate, which offers a solution for assaying a large number of rat urine samples within a short time. This kit requires a minimal volume (less than 10 μl) of urine samples, and is ideal for studying nephritis in various strains of rats that do not secrete enough volume of urine during a 16-hour collection period.

Rat Urinary Protein Assay Kit and Standard

Product Quantity Catalog # Price (USD)
Rat Urinary Protein Assay Kit 1 Kit 9040 112.00
Rat Urinary Protein Assay Standard 90401 63.00

Turbidity Assay and Bradford Assay

The turbidity assay method has been widely used to determine urinary protein levels in human specimens, because it is accurate, easy to use, and economical. However, the current turbidity method requires a large volume of samples, and cannot be used for assaying urine specimens from certain strains of rats, because of low urine volumes. Please note that the16-hour urine volume varies significantly from 0.1 to 20 ml depending on rat strains. Furthermore, reading turbidity (OD 450 nm) of individual test tubes using a spectrophotometer is time consuming. 

Protein concentrations in urine samples can be determined by Bradford assay methods. However, turbidity assay method using 3% sulfosalicyclic acid dihydrate is more convenient than the Bradford method because of the wide range of dose response curve.  Importantly, regardless of which assay method is used, bovine serum albumin (BSA) cannot be used as a standard. The dose response curve of BSA significantly differs from the dose response curve of serum proteins in turbidity assay. More importantly, the OD value of globulins by Bradford assay method is only 70% of the value of BSA. Therefore, a standard protein solution prepared from normal rat serum is ideal for assaying urinary protein levels regardless of the assay method.

Standard curve of Chondrex, Inc Rat Urinary Protein Assay Kit. Standards are from 0.0 mg/ml to 4.0 mg/ml of protein, with OD values from 0.00 to 1.30.

Figure 1 - Standard curve of rat urinary protein assay by turbidity method in 96-well plate