Chapter 7 Urinalysis

What is a urinalysis?

an examination of urine to determine the presence of abnormal elements that may indicate various pathologic conditions

A urinalysis is an ______ and _____ test that provides information on the contents of urine and diseases affecting the body as a whole.

inexpensive; noninvasive

True or false: a urinalysis can be done in an office setting, and the results are almost instant.

true

What color should urine typically be?

yellow (amber), or straw-colored

What does a smoky-red or brown color of urine indicate?

the presence of large amounts of blood

What does cloudy or turbid urine indicate?

a urinary tract infection with pus (pyuria) and bacteria (bacteriuria)

What is the pH of normal urine?

6.5 (slightly acidic)

When urine tests positive for protein, what is normally responsible for this?

albumin

What is albumin?

a major protein in blood plasma

When albumin is detected in urine (aluminuria), what does it likely indicate?

a leak in the glomerular membrane, which allows albumin to enter the renal tubule and pass into the urine

What are smaller amounts of albumin called?

microalbuminuria (this is known as the earliest sign of renal involvement in diabetes mellitus)

True or false: Sugar is commonly found in the urine.

false

What is diabetes mellitus?

when there is excess sugar in the bloodstream, which leads to the “spilling over” of sugar into the urine

What does the specific gravity of urine reflect?

the amount of waste, minerals, and solids in the urine

Because of the presence of ______, patients with diabetes mellitus typically have a higher-than-normal specific gravity.

sugar

When are ketones formed?

when fatty acids are broken down in the liver

When the body breaks down ___, instead of sugar, for fuel, ketones will accumulate.

fat

When does ketonuria occur?

when cells deprived of sugar must use up their available fat for energy

Why are ketones in the blood dangerous?

they increase the acidity of the blood; this could lead to coma or death

What type of abnormal particle may settle at the bottom of a urine sample?

settlement; epithelial, white, or red blood cells, bacteria, crystals, and casts

What are casts?

cylindric structures of protein often containing cellular elements

What is phenylketonuria (PKU)?

a rare condition in which a baby is born unable to break down an amino acid, phenylalanine. This results in high blood levels of phenylalanine and can lead to intellectual disabilities.

How is the new PKU test performed?

by pricking the newborns heel to obtain a blood sample

If a baby tests positive for PKU, what often has to happen?

they must remain on a diet that excludes phenylalanine, sometimes going into adulthood

What substance gives urine its yellow color?

bilirubin