Examination of normal urine

Requirements:

Glassware: Test tube, test tube stand, beaker, burner, funnel, filter paper.

Chemicals: Ammonium hydroxide, dilute acetic acid, Concentrate Nitric acid, Ammonium molybedate, Potassium oxalate, Silver Nitrate solution, Hydrochloric acid, Barium chloride, Picric acid, Sodium hydroxide.

Theory: Urine is the major route for water loss from the body. In a healthy individual the urine output is about 1-2 l/day. Water loss through kidney although highly variable is well regulated to meet the body demands to get rid of water or to retain. It should however, be remembered that man cannot completely shut down urine production, despite there being no water intake.

Composition of urine

Water: It is the largest component of urine. It makes about 95% of total urine.

Inorganic components: This contains two types of ions i.e. cation and anion. Major cations are sodium (Na+), potassium (K+), calcium (Ca+2), magnesium (Mg+2), ammonium (NH4+), iron (Fe+2), copper (Cu+2), zinc. Chief anions are chloride (Cl-), phosphate (PO4-3), sulphate (SO4-3), bicarbonate (HNO3-), Nitrate (NO3-) etc.

Organic compounds: The principle nitrogenous constituents are urea acid, creatinine, hippuric acid, purine base and amino acid.

Procedure Physical examination

(a) Appearance: Normal urine is clear and transparent when freshly collected.
(b) Color: Normal urine is pale yellow colour. This colour is due to pigment urochrome.
(c) Odor: Freshly collected urine has characteristic aromatic odor due to the presence of some volatile organic acid.

Chemical examination

Their are different test for urine examination. They are given below-

Test for Ammonia

Take three mL fresh urine in the test tube and heat then put red litmus paper over the mouth of test tube. Litmus paper turn blue confirm the presence of ammonia.

Test for Calcium and Phosphate

Take 5 mL urine in test tube and add little amount of ammonium hydroxide  and boil and white flanky precipitate form, filter the content and dissolve the residue in 3 mL of diulte acetic acid them collect the filterate and divide in two part. (

a) In first part add few drop of concentrate nitric acid followed by ammonium molybedate then boil. Formation of lemon yellow color precipitate indicates the presence of phosphate. 

(b) In second part add one mL potassium oxalate solution. Formation of white precipitate indicates the presence of calcium.

Test for chloride

Take 2 mL urine in the test tube and add few drop of concentrate nitric acid followed by two mL of silver nitrate solution. Formation of white precipitate confirms the presence of chloride.

Test for sulphate

Take 3 mL urine in test tube and add few drop of concentrate hydrochloric acid then one mL of barium chloride solution. Formation of white precipitate indicates the presence of sulphate.

Test for creatinine or Jaff’s test

Take 3 mL of picric acid solution in the test tube and add 0.5 mL of sodium hydroxide solution and divide into two parts. 

(a) In first test tube add 2 mL urine. Deep reddish orange colour confirms the presence of creatinine. 

(b) In second part add 2 mL water; no colour change indicates the absence of creatinine.

Result: In the urine Ammonia, Chloride, Phosphate, Calcium, Sulphate, and creatinin urea present. They are confirmed by ammonia test, calcium, phosphate test, chloride test, sulphate test, and creatinin test respectively.