Chemical Examination of Urine, pH, Urine protein, Suphosalicyclic acid method, Boiling and acetic acid method, By test strips (Albym & Ablustix)

 

 pH :- 

An indicator paper strips with a range of 1 to 12 is used to determine the pH of urine, if urine sample is acidic or alkaline.

The paper strip is dipped in urine sample and the colour change is matched with the colour of litmus paper colour chart that is provide with the strip.

There are available multistix reagent strips that is used to determine pH. It works as the same principle as indicator strips.

The pH of the urine also determined by the pH indicator. Which can be prepare by adding 2 drops of 0.4% alcoholic solution of methyl red in to 5ml of urine sample.

Detection of proteins.

 click here to watch:- Physical examination of urine

click here to watch:- Estimation of Urea Berthelot method.

Observe the colour-

 Red colour. …Acid

Orange colour… . Neutral

Yellow colour… ..Alkaline

 

Detection of Proteins:-

 When Protein present in urine this condition is called the proteinuria. Normal urine contains trace of protein . This protein derived from the plasma albumin, plasma globulin, Haemoglobin and other related products of red blood cells. If urine is contaminated with vaginal, pus, semen, then protein may be found. It is therefore essential to collect the mid-stream urine.

 

Protein detection :-

Protein detection by-

Qualitative test

Quantitative test..

 

Qualitative test:-

 

•                     Boiling and acetic acid test

•                     Sulphosalicyclic acid test

•                     Test strip for protein

Detection of proteins.

 

1. Boiling and acetic acid :-

 

Principle-

Proteins are coagulated by heat in acidic urine and do not dissolve on acidification.

Whereas phosphates and carbonates which are also precipitated by heat, I and dissolve in acid.

 

Method-

 •                     When urine is clear then use directly for the following procedure.

 •                    If urine is not clear, First of all filter and centrifuge the urine, if urine is        

            alkaline make slightly acid with 2-3 drops of 5% acetic acid.

 

1.   Test a test tube and fill it with (2/3) with clear urine.

2.    Hold the test tube at an angle away from you,

3.    Heat the upper portion of the of the urine until it start boiling.

4.    Cloudiness / turbidity will rise in the presence of protein, carbonate and      

        phosphates.

5.    Then add few drops of 5% acetic acid and start boil again.

6.    If turbidity development / persistence indicates proteinuria.

7.    If turbidity disappear it is due to the presence of carbonates and     

       phosphates.

 

Results –

 No cloudiness _             - (nil)

 Trace cloudiness _           +/-

 Definite cloudiness _        +

(with no flocculations)

 Granular cloudiness _        ++

(no flocculation)

 Dense, opaque cloudiness _ +++

( Clear flocculation)

 Thick precipitation _ ++++

 

2. Sulphosalicyclic acid test:-

 

Principle-

 Sulphosalicyclic acid, being an anionic precipitant, neutralises the protein cation , then resulting in the precipitation of proteins.

 Method-

 •                    Take one ml of clear urine.

•                     Add 3 drops of 25% Sulphosalicyclic acid.

•                     If protein present, Precipitate is formed.

 

Note.. False positive results if urine contains a high concentration of penicillin.

 

Results –

 No cloudiness _                  -  (nil)

 Trace cloudiness _                +/-

 Definite cloudiness _             +

(with no flocculations)

 Granular cloudiness _            ++

(no flocculation)

 Dense, opaque cloudiness _ +++

(clear flocculation)

 Thick precipitation _              ++++

 

 

3. Test strip used for protein :-

1. Albustix

2. Albym

1. Albustix

 Principle-

 In the strip tetrabromo-phenol blue is yellow colour at pH 3.0, but changes the colour to bluish green at the same pH 3.0, in the presence of protein.

 

Method-

 •                     Collect the fresh urine sample.

•                     Dip the test end of the strip in the sample for one second.

•                     Drain off the excess urine.

•                     Compare the colour of the strip with the colour chart (i. e given on the    

              tests trip bottle) within 60 seconds.

•                     Colour changes from yellow to bluish green indicate presence of    

              protein.

 

2. Albym method-

 Principle-

 The indicator used in tetrabromophenol-phthalein ethhyl ester. It produces green colour even if in the presence of small concentration of protein.

 

Method –

 •                    Collect the fresh urine sample.

•                     Dip the test end of the strip in the sample for one second.

•                     Drain off the excess urine.

•                     Compare the colour of the strip with the colour chart (i. e given on the    

              teststrip bottle) within 60 seconds.

•                     Colour changes from yellow to bluish green indicate presence of    

              protein.

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