What is alkaline picrate method?
Principle. Picric acid in an alkaline medium reacts with creatinine to form a orange coloured complex with the alkaline picrate. Intensity of the colour formed is directly proportional to the amount of creatinine present in the sample.
What is the Jaffe method?
The Jaffe reaction is a colorimetric method used in clinical chemistry to determine creatinine levels in blood and urine.
Why NaOH is used in Jaffe’s method?
Without taking into consideration the acidic nature of standard, protein free filtrate (PFF) of serum and urine, 1% picric acid and 0.75N NaOH are used in this reaction for color development in standard, PFF of serum and urine. Alkali is consumed to neutralise the acids in both these cases.
Which method is used for estimation of creatinine?
Still, creatinine remains the gold standard for measuring the glomerular filtration rate and kidney functioning. And Jaffe method remains the default method for estimation of creatinine.
How do you make an alkaline picrate solution?
Alkaline picrate solution: Mix 5 volumes of saturated picric acid solution to one volume of NaOH. creatinine in 0.1 N HCl and diluted to 1 litre with acid. Working solutions : Dilute 3 ml of stock solution to 500 ml with water using 50 ml of 0.1 N HCl (0.006 mg/ml).
What is difference between urea and creatinine?
Urea and creatinine are nitrogenous end products of metabolism. Urea is the primary metabolite derived from dietary protein and tissue protein turnover. Creatinine is the product of muscle creatine catabolism. The normal range of urea nitrogen in blood or serum is 5 to 20 mg/dl, or 1.8 to 7.1 mmol urea per liter.
Which method estimates blood creatinine level most accurately?
Enzymatic creatinine assay
Enzymatic creatinine assay. Widely accepted as one of the most accurate routine methods available at present and data in Table 3 indicates that this method produces results for patient samples that agree closely with IDMS.
How do you make alkaline picrate solution?
The alkaline picrate solution was made up immediately before use by adding 1 vol. of sodium hydroxide to 5 vol. of picric acid. The optical density of the developed color was measured at a wavelength of 520 ml using water as reference optical density.
Why alkaline picrate filters are used at wavelengths below 500 mi?
But at wavelengths below 500 ml the optical density of alkaline picrate (i.e. the reagent blank) is also high. Consequently filters having maximum transmission at wavelengths above 500 mi. have generally been used.
What is the absorption spectrum of alkaline creatinine picrate?
The absorption spectrum of alkaline creatinine picrate shows maximum absorption in the region of 490 mu. But at wavelengths below 500 ml the optical density of alkaline picrate (i.e. the reagent blank) is also high. Consequently filters having maximum transmission at wavelengths above 500 mi. have generally been used.
What is Folin’s colorimetric method?
The first of Folin’s colorimetric methods was that for creatinine, an application of a colour reaction of that substance with picric acid noted by Jaffe many years earlier.