A Complete Guide to URINALYSIS What is it

A Complete Guide to URINALYSIS

What is it and why is urinalysis done…. p The evaluation of urine by various types of testing methods Physical p Chemical p Microscopic p To screen for certain substances or to diagnose various medical conditions p There are normal values for all tests reflected as ‘negative or none’, or it may be a range in concentration. p

Urine is produced by the kidneys to maintain blood chemistry p To regulate Ph, electrolyte and fluid balances…… p To excrete waste p

When to do urinalysis…. . p Usually part of a complete physical exam to screen for certain substance or diagnose various medical conditions p A new pregnancy evaluation p If patient complains of: n n Abdominal pain Back pain Painful or frequent urination Blood in the urine

Preservation and Storage p Changes in the chemical or microscopic properties of urine occur if kept at room temp for more than an hour p Refrigeration- most common method of storing and preserving urine § Prevents bacterial growth for 24 hours § After 24 hours use chemical preservation

Chain of Custody q You may need to obtain urine specimens for drug and alcohol analysis for medicolegal matters q If procedure not followed exactly, you have broken the chain and urine is not admissible. q Thoroughly explain procedure and have the patient sign consent form

How to do urinalysis…. MACROSCOPIC URINALYSIS p The first part of urinalysis is direct visual observation p Quality Assurance- make sure there is no visible contamination and no more than 1 hour has passed since collection or since being brought back to room temp from refrigerator p Observing for: p p Color and Turbidity Volume Odor Specific Gravity

Urine Color and Turbidity p Color n n n Normal- pale yellow (straw colored) to dark amber Yellow color comes from a pigment called ‘urochrome’ Depends on food/fluid intake, medications (including vitamin supplements), and waste products in urine Pale=dilute Dark=concentrated

Abnormal Urine Colors RED = Blood in urine, beets, black berries, hepatitis ORANGE = Rimfampin, pyridium, blood in urine, dehydration, jaundice DARK BROWN OR BLACK= Acute glomerulonephritis, nitrofurantoin, iron preparations GREEN = Bile duct obstruction, vitamin B, asparagus BLUE = methylene blue dye used in medications CLEAR OR STRAW = Diabetic therapy, excessive fluid intake (beer, water, coffee), anxiety, chronic renal disease

Urine Turbidity p Normal n p Clear to slightly cloudy Abnormal n n Cloudy- infection, inflammation, vegetarian diet Milky white- fats, pus

Urine Odor p Normal n p distinct but not unpleasant “aromatic” Abnormal n n Foul smelling= bacterial infection Fruity= uncontrolled diabetes (ketones) Mousy= phenylketonuria (congenital metabolic disease) Foods= asparagus, garlic, onion

Urine Volume p Normal n n n p Adult 600 to 1800 milliliters every 24 hours (average of 1250 ml) Children and infants have smaller total volumes Intake and output should be approximately the same Abnormal n n Oliguria- insufficient production; causes can be dehydration, decreased fluid intake, shock, renal disease Anuria- absence of urine production; causes can be renal or urethral obstruction and renal failure And now for a dumb fact… About one-third of Americans flush while still sitting on the toilet!

Urine Specific Gravity p A measure of the concentration or amount of substances dissolved in urine n n n An indicator of kidney function Normal Range is 1. 005 to 1. 030 Increased SG= more concentrated urine (darker), kidneys not properly diluting urine § Conditions such as UTI, dehydration (fever, vomiting, dehydration), adrenal insufficiency, hepatic disease n Decreased SG= kidneys not properly concentrating urine (lighter) § Conditions such as overhydration, diabetes insipidus, chronic renal disease

Specific Gravity = weight of sample weight of distilled water Urine Specific Gravity p Three methods: n Urinometer p Urinometers are used to measure the specific gravity of urine; one floats the device in a tube of urine and reads off the number at the meniscus.

n Refractometer Optical instrument that measures the refraction or bending of light as it passes through a liquid p The degree of refraction is proportional to the amount of dissolved material in the liquid p

n Reagent Strip (Dipstick) n There are test pads along the strips containing chemicals that react with substances in the urine and change color (will discuss these more in lab next week)