Diagnostics Urinalysis

How to get the best sample

midstream, first morning void, examined within 30 min

What are the 3 components of a urinalysis

1. gross exam

2. dipstick chemical test

3. microscopic exam

What are components we look for in gross exam of urinalysis

Color, clarity

What are some chemical components we look for in urinalysis

pH, protein, glucose, ketones, bilirubin, hemoglobin

what is normal urine pH range

5-7

Clinical usefullness of knowing urine pH

renal stones can form in acidic urine, medications can be used to acidify or alkalinize urine to treat some medical conditions

Very dilute urine is seen in

diabetes insipidus

Very concentrated urine is seen in

dehydration, proteinuria, glycosuria

What is a normal urine protein dipstick

negative

Glomerular filtration barrier does not allow significant filtrate of proteins so proteinuria means

damage to glomeruli

Mild proteinuria can be seen in

UTI, fever

Chronic proteinuria can be seen in

chronic or acute kidney damage

Normal urine glucose

negative

when does glucose appear in urine

BGL exceeds reabsorption capacity by convoluted tubule

abnormal urine glucose can be due to

diabetes mellitus or some medications

Normal urine ketones

negative

what are ketones products of

fatty acid metabolism

what can positive result indicate

breakdown of fatty acids instead of glucose for energy

Who can positive ketones be seen in

diabetes mellitus, starvation, low carb diets

Normal bilirubin test

negative

what does positive bilirubin test indicate

hepatobiliary disease

Bilirubin can be detected on

dipstick, finding may be ealy sign of liver disease

normal urine hemoglobin

negative

when is hemoglobin positive in urine

hematuria, hemoglobinuria, myoglobinuria

What does positive urine nitrite test suggest

presence of bacterial UTI, check urine culture

Does a negative urine nitrite mean pt cannot have UTI

NO, check urine culture to be sure

What does positive urine leukocyte esterase mean

presence of WBCs in urine (infection/inflammation), check urine culture if +

Urinaalysis microscope exam evaluates for

RBCs, WBCs, bacteria, yeast, crystals, casts

What is a urine cast

precipitated proteins in renal tubules that mold to the lumen and take on that shape. Pieces break off and end up in urine

types of urinary casts

hyaline, hyaline-granular, waxy, erythrocyte, hemoglobin, leukocyte