The yellow color of urine is caused by the presence of the pigment urochrome, a product of metabolism that under normal conditions is produced at a constant rate. The actual amount of urochrome produced depends on the body’s metabolic state, with increased amounts being produced in thyroid conditions and fasting states.

Urine specimens may vary in color from pale yellow to dark amber. Variations in the yellow color are related to the body’s state of hydration. The darker amber color may be directly related to the urine concentration or SG. Blood in the urine may cause it to appear pink, red, brownish-red, or tea-colored.

The normal color of urine is pale yellow to amber.

Straw-colored (almost colorless) urine is normal and indicates a low SG, usually <1.010. (The exception may be a patient with an elevated blood glucose concentration, whose urine is very pale yellow but has a high SG.)

Amber-colored urine is normal and indicates a high SG and a small output of urine.

Observe and record the color of freshly voided urine.

1. Straw-colored (almost colorless) urine

   1. Large fluid intake

   2. Chronic interstitial nephritis

   3. Untreated DM

   4. Diabetes insipidus

   5. Alcohol and caffeine ingestion

   6. Diuretic therapy

   7. Nervousness

2. Amber (orange-colored) urine

   1. Concentrated urine caused by fever, sweating, reduced fluid intake, or first morning specimen

   2. Bilirubin present (produces yellow foam when shaken)

   3. Carrots or vitamin A ingestion (large amounts)

   4. Certain urinary tract medications (e.g., phenazopyridine [Pyridium], nitrofurantoin)

3. Brownish yellow or greenish yellow urine may indicate bilirubin in the urine that has been oxidized to biliverdin (produces greenish foam when shaken).

4. Green urine

   1. Pseudomonal infection

   2. Indican

   3. Chlorophyll

5. Pink to red or tea-colored urine

   1. RBCs

   2. Hemoglobin, methemoglobin, oxyhemoglobin

   3. Myoglobin

   4. Porphyrins

6. Brown-black urine

   1. RBCs oxidized to methemoglobin

   2. Methemoglobin

   3. Homogentisic acid (alkaptonuria)

   4. Melanin or melanogen

   5. Phenol poisoning

7. Smoky urine may be caused by RBCs.

8. Milky urine is associated with fat, cystinuria, large amounts of WBCs, or phosphates.

Pretest Patient Care

1. Explain purpose of test, procedure for urine collection, and interfering factors.

2. Assess color of urine; instruct patient to monitor and to report abnormal urine colors.

1. Normal urine color darkens on standing because of the oxidation of urobilinogen to urobilin. This decomposition process starts about 30 minutes after voiding.

2. Some foods cause changes in urine color:

   1. Beets turn the urine red.

   2. Rhubarb can cause brown urine.

3. Many drugs alter the color of urine:

   1. Cascara and senna laxatives in the presence of acid urine turn the urine reddish brown; in the presence of alkaline urine, they turn the urine red.

   2. Bright-yellow color in alkaline urine may be a result of riboflavin or phenazopyridine.

   3. Urine that darkens on standing may indicate antiparkinsonian agents such as levodopa.

   4. Black urine may be caused by cascara, chloroquine, iron salts (ferrous sulfate, ferrous fumarate, ferrous gluconate), metronidazole, nitrofurantoin, quinine, or senna.

   5. Blue urine may be caused by triamterene.

   6. Blue-green urine may be caused by amitriptyline, methylene blue, or mitoxantrone.

   7. Orange urine may be caused by heparin, phenazopyridine, rifampin, sulfasalazine, or warfarin.

   8. Red-pink urine may be caused by chlorzoxazone, daunorubicin, doxorubicin, heparin, ibuprofen, methyldopa, phenytoin, rifampin, or senna.

   9. Pink to brown urine may be caused by laxatives.

   10. Brown urine may be caused by chloroquine, furazolidone, or primaquine.

   11. Green urine may be caused by indomethacin.