JPS6038666B2 - Creatinine measurement reagent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reagent set for rapidly, accurately, and simply measuring creatinine in body fluids.

Creatine is a normal component of muscle, and combines with phosphate to become an energy source for muscle contraction, producing creatinine as a metabolite. Creatinine is an anhydrous form of creatine that is absorbed in the glomerulus and then excreted in the urine without being reabsorbed. Therefore, measurement of creatinine provides useful information for diagnosing renal diseases such as glomerular failure and pharyngitis caused by severe glomerular lesions, uremia, and muscular atrophy, and for observing the progress of treatment. Several methods have been published for measuring creatinine in biological samples, but none of them are far from perfect. The only practical method used is the Folin method, in which the active methylene groups of creatinine are condensed with alkaline picric acid and the resulting condensate is determined colorimetrically.

However, this measurement method is not a specific reaction to creatinine, and all other active methylene group-containing substances result in positive errors. Fortunately, the absorption of creatinine is on the longest wavelength side, so it is said that many substances do not substantially interfere with measurements, but proteins, whose condensates are located close to creatinine condensates, Since it is absorbed and is present in large amounts in serum, it is impossible to measure it as is, requiring protein removal, and the operation is complicated, so accuracy and speed are required. This was a major drawback in the clinical tests performed. The present inventors conducted extensive research and found that a first reagent consisting of an alkaline aqueous solution and picric acid,
By combining lauryl sulfate and a second reagent whose main ingredients are a nonionic surfactant, protein removal is not required.
We have discovered a complete reagent or method for measuring creatinine that is stable and solves all the shortcomings of conventional measurement methods, and have completed the present invention. As the first reagent made of an alkaline aqueous solution, for example, an alkaline aqueous solution of caustic soda, caustic potash, or the like is used.

The second reagent contains picric acid, lauryl sulfate, and a nonionic surfactant as main ingredients, and preferably contains a preservative to prevent the formation of mold due to dilution.

Salts such as sodium or potassium lauryl sulfate bind to proteins and have the function of effectively suppressing the reaction with picric acid. Nonionic surfactants work to solve the problem of precipitation of lauryl sulfate during winter storage or measurement. Cationic and anionic surfactants are unsuitable for use because they cause problems in suppressing the reaction with picric acid and have poor effects as lauryl sulfate solubilizers. As the nonionic surfactant used in the present invention, any surfactant that is water-soluble and does not precipitate under acidic or basic conditions can be used. Examples of these include polyoxyethylene lauryl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene sorbitan monolaurate, polyethylene glycol cetyl ether, and the like. As preservatives to prevent the growth of mold due to aging, common preservatives such as benzoic acid and sorbic acid can be used without any problems. As described above, since the measurement reagent of the present invention does not require protein removal, it is possible to measure creatinine extremely simply and accurately, and it greatly contributes to diagnosis and medicine.

The present invention will be further explained with reference to Examples below.

In the examples, all parts expressed are parts by weight. Example 1
(Example of reagent preparation) Dissolve caustic soda in water to make a 0.5N solution.

This is an example of the first reagent. 0.2 part of picric acid, 0.8 part of sodium lauryl sulfate, 0.4 part of polyoxyethylene lauryl ether, and 0.1 part of sodium benzoate are dissolved in distilled water to make a total amount of 100 parts.

This is an example of the second reagent. Sodium lauryl sulfate 0
．． Part 8 “Polyoxyethylene lauryl ether 0.4
1 part and 0.1 part of sodium benzoate were dissolved in distilled water to make a total of 10 parts.

This is an example of Planck's solution. Example 2 (Example of Creatinine Measuring Method) Fifty doses of the same serum are placed in two test tubes, one for the main test and the other for the blind test.

For the main test, the first reagent 2' and the second reagent 2' of Example 1 were used.
For blind testing, add 1st reagent 2' and blank solution 2'.
Add. After standing at 25°C for 10 minutes, the difference in absorbance was determined using the blind sample as a control.

Claims (1)

[Claims] 1 A first reagent consisting of an alkaline aqueous solution and a second reagent consisting of picric acid, lauryl sulfate, and a nonionic surfactant as main ingredients.
A reagent for measuring creatinine in body fluids, characterized in that it is a set of reagents.