- Normally color of urine may vary within a day.
Normal urine color :
- Amber yellow.
• Normal urine color results from three pigments :
1. Urochrome: yellow color formation.
2. Uroerythrin: red color formation.
3. Urobilin: orange-yellow color formation.
• Abnormal color :
1. Pale to colorless :
Indicate to :
1. Large fluid intake.
2. Diabetic mellitus.
3. Diabetic insipidus.
4. Alcohol consumption.
5. Nervousness.
2. Dark yellow color :
Indicate to :
1. Concentrated urine.
2. Decreased fluid consumption.
3. Dehydration.
4. Fever.
5. Certain urinary tract medication.
3. Clear red color :
- indicate presence of Hemoglobinuria (presence of hemoglobin in the urine):
1. Incompatible blood transfusion.
2. Increased red blood cell destruction (intravascular haemolysis).
3. Glucose – 6-phosphate dehydrogenase deficiency.
4. Certain infections or disease.
• Cloudy red color :
- may indicate hematuria (presence of red blood cell in the urine).
- It differs from clear red by the presence of RBC rather than Hgb alone. It is important to differentiate hemoglobinuria from hematuria, because the cause of this abnormal urine differs.
4. Yellow green +yellow foam :
- may indicate the presence of bilirubin.
5. Dark brown color :
- urine may contain porphyrines, melanin, homogenstic acid, associated with an abnormal metabolism of tyrosine.
6. Milky urine :
- urine may contain fat, cystine crystals, and many WBC or amorphous phosphates.
7. Dark reddish color :
- may indicate myoglobin (muscle Hgb), associated with extensive muscle injury, hemoglobinuria and porphyrine.
Normally fresh voided urine from healthy individuals has faint aromatic odor, which comes from volatile acids, normally found in urine, mostly, ammonia.
- Abnormal urine odor may result from aging of urine, disease and diet:
1. ammonical (pungent) odor :
- due to break down and conversion of urea in the urine into ammonia by the action of bacteria.
2. sulfurous odor :
- due to cystinuria and homocystinuria (type of amino acids, voided from abnormal metabolism).
3. brewery (yeast) :
- smell associated with oasthouse urine disease.
4. fishy odor cause by Tyrosenemia.
5. sweet fruity odor :
- Due to presence of ketone bodies in the urine.
• Cloudy red color :
- Transparency : Fresh voided urine specimen is normally clear and transparent.
• Degree of cloudiness of the urine is described by using common terms, starting by clear to turbid i.e. clear, hazy, cloudy, very cloudy and turbid.
- Causes of turbid urine :
1. White blood cells (pus cells) in UTI.
2. Kidney stones.
3. RBC’s.
4. Yeast cells.
5. High number of bacteria cells.
6. High number of epithelial cells.
7. Fat droplets in urine, which give opalescent appearance.
8. Amorphous urates, in case of gout and leukemia.
9. High number of mucus trades.