Urinalysis
Characteristics of Urine
Chemical Composition of Urine
Abnormal Urinary Constituents
Abnormal Urinary Constituents Cont'
100
What are the normal ranges for the constituents of urine?
Color - Pale yellow to amber or dark yellow, Clarity - Clear, Odor - Slightly aromatic "nutty odor", Specific Gravity - 1.001 - 1.030, pH - 4.5 - 8.0, Protein - None, Glucose - None, Ketones - None, Nitrite - None, Leukocytes (WBC) - None,
100
What else besides solute concentration changes the color of urine?
Certain foods such as beets, various drugs, bile, or blood.
100
What is specific gravity and what is the normal range for urine?
Specific gravity is the relative weight of a specific volume of liquid compared with an equal volume of distilled water. Since urine contains dissolved solutes, it weighs more than water. Urine's specific gravity ranges from 1.001 to 1.030.
100
The presence of Glucose in the urine occurs in what condition and indicates abnormally high levels of what in the body?
The presence of glucose in the urine occurs in a condition called glycosuria or Diabetes and indicates abnormally high levels of sugar in the body. Normal sugar levels are maintained between 80 and 100mg/100ml of blood. All glucose is normally reabsorbed in the proximal convoluted tubule.
100
What are casts?
Casts are hardened cell fragments, usually cylindrical, which are formed in the distal convoluted tubules and collecting ducts and then flushed out of the urinary tract.
200
How much blood plasma is filtered through the glomeruli into the tubules of the nephrons in a 24hour period?
150 to 180 liters
200
The odor of freshly voided urine should be what and why does this odor change if the urine is left standing?
The odor of freshly voided urine is slightly aromatic and will have an ammonia-like odor if left standing, due to bacterial action.
200
Urine with a specific gravity of less than 1.001 would be considered what and how does this occur?
Urine with a specific gravity of less than 1.001 would be considered dilute because it contains few solutes. Dilute urine commonly results when a person drinks excessive amounts of water, used diuretics, or suffers from Diabetes Insipidus or chronic renal failure.
200
What does the presence of Albumin in urine indicate about the permeability of the glomerular filtration membrane?
Albumin, like all other blood proteins is too large to pass through the glomerular filtration membrane. Thus, albuminuria is generally indicative of abnormally increased permeability of the glomerular membrane and decreased colloid osmotic pressure in the capillaries.
200
Why do casts form in the distal convoluted tubules and what are RBC and WBC casts called?
Casts form when the filtrate flow rate is slow, the pH is low, or the salt concentration is high (all conditions which cause protein to denature). Red blood cell casts are typical in glomerulonephritis and form when RBC's leak through the filtration membrane and stick together in the tubules. White blood cell casts form when the kidney is inflamed, which is typically a result of pyelonephritis.
300
What processes take place in the tubules?
Re-absorption and secretion
300
What would the urine of a person who has uncontrolled Diabetes Mellitus smell like and why?
The urine of a person who has uncontrolled Diabetes Mellitus would smell fruity or acetone-like due to the elevated levels of ketones in the urine.
300
What conditions would produce urine with a high specific gravity?
Conditions that produce urine with a high specific gravity include limited fluid intake, fever, and kidney inflammation called pyelonephritis.
300
What does the presence of Ketone bodies in urine indicate?
Ketone bodies in the urine indicates that abnormal metabolic processes are occurring. Ketonuria is an expected finding during starvation. Ketonuria coupled with Glycosuria is indicative of Diabetes Mellitus. Ketones are often found in the urine when a person does not eat (fasts) for 18 hours or longer. This may occur when a person is sick and cannot eat or vomits for several days.
300
What does the presence of nitrites in urine indicate?
The presence of nitrites in urine indicates the presence of a bacterial infection, most likely E-coli. Nitrites are also valuable for early detection of bladder infections.
400
What is the color of normal urine depending on solute concentration relative to water?
Pale yellow to amber in color depending on solute concentration
400
In the presence of a bacterial infection, what would the pH of urine be?
high or greater than 8.0
400
If urine becomes excessively concentrated, some of the substances normally held in the solution begin to precipitate or crystallize forming what?
Renal calculi commonly known as kidney stones
400
What does Hematuria the appearance of red blood cells or erythrocytes in the urine indicate?
The appearance of red blood cells or erythrocytes in the urine indicates pathology of the urinary tract because erythrocytes are too large to pass through the glomerular pores. Possible causes include irritation the urinary tract organs by kidney stones, bleeding or infections or tumors of the urinary tract. In females, red blood cells in the urine could also mean accidental contamination of the urine sample with menstrual blood flow.
400
What does the presence of bile pigments in urine indicate?
Bilirubinuria or the presence of bile pigments in urine usually indicates liver pathology, such as hepatitis, cirrhosis or bile duct blockage. Bilirubinuria is signaled by a yellow foam that forms when the urine sample is shaken.
500
What is the normal pH range for urine?
4.5 to 8.0
500
What is the mathematical formula for specific gravity?
Density of the Sample/Density of water
500
What are the normal constituents of urine in order of decreasing concentration and what is the percent of water to solute ratio?
The normal components of urine in order of decreasing concentration include water, urea, sodium potassium, phosphate, and sulfate ions, creatinine, and uric acid and much smaller but highly variable amounts of calcium, magnesium and bicarbonate ions are also found in urine. The percent of water to solute ratio in urine is 95% water to 5% solute.
500
What could the presence of hemoglobin in the urine, also called Hemoglobinuria indicate?
The presence of hemoglobin in the urine, is the result of fragmentation, or hemolysis of red blood cells. It may indicate hemolytic anemias, transfusion reactions or renal disease.
500
What does the presence of white blood cells in urine or pyuria indicate?
The presence of white blood cells in urine or pyuria indicates the presence of pus in the urine which indicates inflammation of the urinary tract.
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