ANALYSIS OF ABNORMAL CONSTITUENTS IN URINE

 

ANALYSIS OF ABNORMAL CONSTITUENTS IN URINE

 

                Metabolic disorders in most common diseases are readily reflected in the composition of the urine of such patients. So analysis of the urine for such abnormal constituents is of great diagnostic value. Examples are the presence of protein, glucose, blood ketone bodies, bile pigments, bile salts etc.

 

                Many of the pathological constituents are present in trace amounts in normal urine, but they escape detection due to the low sensitivity of the methods employed. The concentration of these constituents in urine are marked, increased in different pathological condition. Usua1ly the analysis is carried out in properly preserved 24hours urine specimens. When this is not possible the early morning specimen can be used. On standing urine undergoes bacterial fermentation, it can be preserved under refrigeration or using chemicals such as toluene or chloroform.

 

A. Physical characteristics in pathological condition:

1) Volume:

                An increase in urinary output (polyuria) occurs in diabetes mellitus and diabetes insipidus and after administration of drugs like digitalis and salicylates etc. A diminished urinary excretion (Oliguria) occur in nephritis, fever and during diarrhea and vomiting. A total suppression or urine formation (anuria) may occur during shock, acute nephritis, incompatible blood transfusion, mercury poisoning and bilateral renal stone formation.

 

2) Colour:

                The urine becomes smoky brown when blood is present. When bilirubin is present the colour will be yellow, melanin makes the urine black. The urine is milky in appearance due to the presence of bacterial or epithelial cells and lipids.

 

3) Reaction:

                Acidic urine is voided in fever and diabetes. Alkali therapy and urinary retention make urine alkaline.

 

4) Specific gravity:

                Specific gravity is increased in acute nephritis and fever and decreased in diabetes in-sipidus.

 

b) Chemical constituents:

                The abnormal constituents which are routinely looked for in urine are albumin, glucose, ketone bodies, bile salts, bilirubin and blood.