Ch. 5: Macroscopic Exam of Urine

Normal urine colors

colorless, pale yellow, dark yellow, amber

abnormal urine colors (5)

• pink/red/reddish brown

  • presence of Hgb or RBCs

• orange

  • pyridium (UTI medication)

• green

  • propofol

• dark yellow-green

  • biliverdin (oxidized bilirubin)

• blue-green

  • “blue diaper syndrome” due to hypercalcemia

What are some causes of nonpathological urine turbidity?

• squamous epithelial cells

• mucus

• normal crystals

• sperm

• fecal contamination

• radiographic contrast media

What are some causes of pathological urine turbidity?

• RBCs

• WBCs

• bacteria

• yeast

• abnormal crystals

• trichomonas

• non-squamous epithelial cells

• lipids

What causes foul, ammonia scented urine?

bacteria and UTIs

What causes fruity/sweet scented urine?

presence of ketones

• in conditions like diabetes mellitus or starvation

What is the cause of mousy or musty scented urine?

The presence of phenylketonuria (PKU), a metabolic disorder

Why might urine be foamy?

• due to excess protein in the urine (proteinuria)

  • severe kidney damage causes proteins to be released into urine

What is the specific gravity of plasma?

1.010

What is the specific gravity of normal urine?

1.003 to 1.035

What does a urine specific gravity of <1.003 indicate?

the urine is diluted

• may suggest conditions such as diabetes insipidus or excessive fluid intake

What does a urine specific gravity of >1.040 indicate?

• the SG is physiologically impossible

• an interfering substance, like radiographic dyes, are present

How is refractometry used for measuring specific gravity?

• total solute is measured

• the refractive index is measured

  • a comparison of the velocity of light in the air with the velocity of light in a solution

• NOTE: larger particles can falsely increase the SG

How does a urine dipstick measure specific gravity?

• chemically

• measures ionic solutes