Physical Examination Of Urine | Urinalysis
Physical examination of urine is also referred to as macroscopic examination and this involves the assessment of physical properties such as volume, color, appearance, odor, foam, specific gravity, and pH.
 |
| Physical Examination Of Urine | Urinalysis |
Physical Examination Of Urine
physical examination of urine include such properties
- volume
- color
- appearance
- odor
- foam
- specific gravity and
- Reaction pH.
 |
| Physical Examination Of Urine | Urinalysis |
1.Volume
Volume:-Under normal conditions, a direct relationship exists between urine volume and the water intake of a person. Thus, if water intake is increased, the kidney will eliminate a larger volume of urine than normal. Likewise, if water intake is decreased, the kidney will eliminate a smaller volume of urine. Certain situations, however, give rise to abnormal urine volumes. Here are some terms to describe such volumes:
The volume of urine for analysis |
|
Normal urine output |
|
Polyuria:- | a large volume of urine (> 2000 ml) in 24 hours |
Diuresis:- | describes an increase in urine volume |
Oliguria:- | The small volume of urine (<200 ml) in 24 hours. |
Anuria | complete absence of urine |
Nocturia | urine more than 500 ml at night |
|
|
Polyuria
Polyuria:- This term refers to consistent elimination of an abnormally large volume of urine (> 2000 ml) in 24 hours. Causes: Diabetes mellitus, Neurotic polydipsia (abnormal thirst), Chronic renal failure
Diuresis
Diuresis:- This is a term that describes an increase in urine volume, even if the increase is only temporary Causes: Excessive fluid intake diuretics drugsIntravenous saline/glucose
Oliguria
Oliguria:- The term refers to the excretion of an abnormally small volume of urine (<200 ml) in 24 hours. Causes: Dehydration due to vomiting, diarrhea, excessive sweating Renal ischemia Acute renal tubular necrosis Acute glomerulonephritis Obstruction to urine flow
Anuria
Anuria:-This is the complete absence of urine formation. Causes: Same as for oliguria
Nocturia
Nocturia:-The excretion, by an adult, of urine more than 500 ml at night is called nocturia. Cause: Chronic glomerulonephritis
Color
Colour- The color of normal urine varies greatly, even in one person, in a single day. In general, the normal urine color is described as straw, yellow, or amber. This color of normal urine is due to the presence of three pigments:
- urochrome (a yellow pigment present in large concentrations)
- uroerythrin (a by-product of red blood cell degradation)
- urobilin (another pigment resulting from red blood cell degradation)
The Color of urine for analysis | |
Color | indications |
The normal color of urine | Pale yellow |
Pale:- | Because of diluted urine |
Dark yellow:- | indicates very concentrated constituents |
Yellow-brown or green-brown:- | presence of bilirubin, |
Orange-red or orange-brown:- | Oxidation of urobilinogen to urobilin. |
Clear red:- | presence of hemoglobin (hemoglobinuria |
Cloudy red This color:- | the presence of intact red blood cells |
Black or dark brown:- | the result from melanin or homogentisic acid |
Black color:- | due to phenol poisoning |
Miscellaneous colors:- |
|
|
|
|
|
There are several abnormal colors of urine of pathological significance and require special attention.
Pale:-
Pale urine suggests that the urine is dilute and may result from conditions such as diabetes mellitus or diabetes insipid us, and in nephritic syndrome.
Dark yellow:-
The dark yellow color indicates very concentrated constituents in a comparatively low volume and is commonly associated with a febrile condition.
Yellow-brown or green-brown:-
Yellow-brown or green-brown is a very characteristic color indicating the presence of bilirubin, which is related to the clinical condition called jaundice. Such specimens foam considerably when shaken, forming a distinct yellow-colored foam. On standing, bilirubin may be colored foam. On standing, bilirubin may be oxidized to biliverdin, a green pigment, imparting a greenish tinge to the urine.
Orange-red or orange-brown:-
orange-red or orange-brown color is derived from the pigment, urobilin. The urine slowly takes on the color on standing due to the oxidation of urobilinogen to urobilin. When shaken, such a urine sample will produce a colored foam. A similar color may be seen after the administration of certain drugs such as aminopyrine.
Clear red:-
A clear red color of urine is indicative of the presence of hemoglobin (hemoglobinuria), the color pigment of red blood cells. This is due to the increased red blood cell destruction in the body resulting from conditions such as incompatible
- blood transfusion reaction
- autoimmune hemolytic anemia
- paroxysmal nocturnal hemoglobinuria
- glucose-6-phosphate dehydrogenase deficiency and certain infections and drugs.
- Hemoglobin/ blood in urine can be detected by occult blood test reagent strips.
Cloudy red This color:-
cloudy red is this color caused by the presence of intact red blood cells rather than hemoglobin. This condition is called haematuria and is differentiated from hemoglobinuria by microscopic examination.
Black or dark brown:-
the black or dark brown color may result from melanin or homogentisic acid. Initially, the urine is colorless when voided, but becomes black on standing. This color should not be overlooked as it may suggest very serious conditions.
Melanin is associated with melanoma, a type of tumor; and homogentisic acid is associated with alkaptonuria or phenylketonuria, a result of an inborn error in the metabolism of tyrosine.
Black color:-
the black color of urine may also be due to phenol poisoning or as a result of a conversion of hemoglobin to methemoglobin.
Milky-white:-
milky-white urine may appear milky white in a condition known as Chyluria. This is seen in a chronic infection by a filarial worm Wuchereria bancrofti. The chyle consists of lymph mixed with particles of digested fat. The urinary sediment may show motile microfilariae.
Miscellaneous colors:-
miscellaneous colors there are various bizarre urine colors such as pink, blue, green, and brown that may result from the ingestion of certain substances such as vitamins, vegetables, fruits, certain chemicals, and dyes. They have no clinical significance but may interfere in some chemical tests.
The Appearance/ Transparency of urine for urine analysis.
Appearance/transparency:- Normally, urine is clear when freshly voided; but it often becomes cloudy when allowed to stand for a certain length of time. This cloudiness is usually due to the precipitation of chemical substances (crystals, or amorphous phosphates and urates) in urine or due to the growth of bacteria. However, cloudiness in freshly voided urine is usually of clinical significance and may be due to the presence of mucus, bacteria, white blood cells or red blood cells, etc.
The degree of transparency of a urine specimen is expressed as clear, hazy, cloudy, or turbid.
The Odour of urine for urine analysis.
Odor:- Normal, freshly voided urine has a characteristic faintly aromatic odor due to the presence of certain volatile acids. Bacterial action occurs when the urine is allowed to stand and this produces an ammoniacal odor. The presence of ketone bodies is indicated by the so-called fruity or sweet odor of urine.
The foam of urine for urine analysis.
Foam:- Normal urine will produce a moderate amount of white foam when shaken. A urine sample with a high protein concentration produces a large amount of white foam on shaking, for example, in nephrotic syndrome. A characteristic yellow-colored foam is seen in urine samples containing bile pigments.
The PH of urine for urine analysis
PH-Regulation of acidity in the extracellular fluid is one of the important functions of the kidney. By checking the pH of the urine, this aspect of kidney function can be determined.
- The pH of blood is normally maintained at 7.4. A blood pH of less than 6.8 or greater than 7.8 can be fatal.
- A high degree of acidity is produced due to carbon dioxide formed during normal metabolism. This acidity is eliminated from the body by the kidneys and the lungs.
Methods of determining urinary pH An indicator paper strip with a range of pH l to 12 is used to determine if a urine sample is acidic or alkaline. The paper strip is dipped in urine and the color change is matched with the color chart provided with the strip.
The Specific gravity of urine for urine analysis.
Specific gravity:- Specific gravity (Sp.gr.) of urine is a measure of the number of dissolved substances in the urine. It is the weight of the urine compared to the weight of an equal volume of distilled water at a constant temperature.
Weight of urine e.g.,
Urines of low specific gravity are called hyposthenuric (<1.007), and those of fixed specific gravity of about 1.010 is called isothenuric.
Causes of high specific gravity The most common causes of high specific gravity of urine are: | Causes of low specific gravity Generally, the low specific gravity of urine is caused by |
(i) Excessive sweating (ii) Glycosuria (iii) Acute nephritis (iv) Albuminuria (v) All causes of oliguria | (i) Excessive fluid intake (ii) Chronic nephritis (iii) Diabetes insipidus (iv) All causes of polyuria except for diabetes mellitus. |
for go back to urine analysis click here
Chemical examination of urine - click here
