URINE TESTING

Urine Testing Uses – Purpose, Characteristics, Examination, Preliminary Assessment, Equipment, Procedure, Urine pH, Gravity, After Care

UPDATED 2024

Urine testing, also known as urinalysis, is a diagnostic test that involves analyzing a person’s urine for various markers, compounds, and characteristics. This type of testing can provide valuable information about a person’s overall health, help diagnose medical conditions, and monitor the effectiveness of treatments.

USES OF URINE TESTING

Here are some common uses of urine testing:

1. Drug Testing: Urine tests are frequently used to screen for the presence of drugs and their metabolites. This is common in workplaces, athletic organizations, and legal situations.
2. Medical Conditions: Urinalysis can help diagnose various medical conditions, such as diabetes, kidney diseases, urinary tract infections (UTIs), and liver problems. Abnormal levels of glucose, protein, blood cells, or other substances in the urine may indicate an underlying health issue.
3. Pregnancy Testing: Urine tests are often used to detect the presence of human chorionic gonadotropin (hCG), a hormone produced during pregnancy. Home pregnancy tests typically use urine samples for this purpose.
4. Kidney Function: Urine tests can provide information about kidney function by measuring levels of creatinine, urea, and other substances. Changes in these levels can indicate kidney problems.
5. Metabolic Disorders: Certain metabolic disorders, such as phenylketonuria (PKU) or maple syrup urine disease (MSUD), can be diagnosed through urine testing.
6. Monitoring Medications: Some medications can be monitored through urine testing to ensure that they are at therapeutic levels and not causing adverse effects.

URINE TESTING

Urine analysis methods comprise testing reaction, specific gravity, albumen, sugar, bile, acetone, pus, blood and yeasts microscopically

Purpose

• To detect reaction, in cystitis the reaction is alkaline
• To detect sugar, it is present in diabetes mellitus
• To detect – protein it is present in kidney damage, pre-eclampsia and is called proteinuria
• To detect acetone, it is present due to incomplete metabolism of fat
• To detect bile – it is seen in cases of obstructive jaundice or hemolytic diseases
• To detect pus cells – it is present due to urinary tract infection
• To detect blood – it is seen in snake bite, fracture pelvis, etc

Characteristics of Normal Urine

• Volume: 1,000 to 2,000 ml in 24 hours
• Appearance: clear
• Odor: aromatic color
• Color: amber or pale straw in color
• Reaction: normal urine is slightly acidic
• Specific gravity: 1.010 to 1.025
• Constituents of the normal urine: water 96 percent, urea 2% and uric acid, urates, creatinine, chlorides, phosphates, sulfates, oxalates – 2% 

Characteristics of Abnormal Urine

Volume

• Polyuria – increased in volume
• Oliguria – decreased in volume
• Anuria – total absence or marked decrease of urine
• Suppression – failure of the kidney to secrete urine

Color

• Green or brownish yellow – bile salts and bile pigments
• Reddish brown – urobilinogen
• Bright red – a large amount of fresh blood
• Smokey brown – blood pigment
• Milk white – chyluria due to filariasis

Appearance

• Mucus – appears as a flocculent cloud
• Pus – settles at the bottom as a heavy cloud
• Stones – as fine sand
• Uric acid – as grains of pepper

Odor

• Sweetish or fruity odor – seen in diabetes

Reaction

• Alkaline – cystitis
• Specific gravity
• Diabetes mellitus – increased specific gravity
• Renal disease – low specific gravity
• Constituents of urine
• Kidney damage – albumin

Types of Examination of the Urine

• Physical examination: color appearance, volume, reaction, specific gravity and color
• Chemical examination: routine tests such as for albumin and sugar. Special tests such as tests for acetone, bile pigments and bile salts. Microscopic examination – crystals, casts, RBC, pus cells, epithelial and bacteria

Preliminary Assessment

• The doctor order for any instructions
• Articles available in the unit
• General condition and diagnosis of the patient
• Self-care ability of the patient

Preparation of the Patient and Environment

• Explain the procedure to the patient
• Keep the urine sample ready
• Arrange the articles ready in the treatment
• Provide labeled container for collecting urine

Equipment

• Test tubes 4 to 6 on a test tube
• Test tube holder – 1
• Spirit lamp – 1
• Match box – 1
• Kidney tray with lining to discard the wastes
• Duster or rag piece – to wipe the outside of the test tube before heating
• Acetic acid – to test urine for albumin
• Nitric acid or sulfosalicyclic acid – to test urine for albumin
• Red and blue litmus paper – to test the reaction of the urine
• Urinometer – to measure the specific gravity of the urine
• Benedict’s solution – to test urine for sugar
• Ammonium sulfate crystals, sodium nitroprusside crystals and liquor ammonia to test urine for acetone
• Weak solution of Tr. Iodine to test for bile pigments
• Sulfur powder: to test for bile salts
• Glass jar: to measure the amount of the urine
• Pipette – 2 – to measure drops of urine and reagents
• A small bottle brush – to clean the test tubes

Procedure

Sugar Test

• Take test tube and fix in holder
• Pour 5 ml of Benedict’s solution into test tube
• Light spirit lamp and heat Benedict solution till it boils
• Holding test tube mouth facing away from nurse
• Add 8 drops of urine using dropper and allow boiling for few seconds
• Put off flame and cool test tube under running water

Observations

• Blue: Nil
• Green: +
• Yellow: ++
• Orange: +++
• Brick red: ++++

Albumin Test

A hot test

• Fill 2/3 of test tube with urine, secure test tube holder at very top
• Heat the upper third of test tube over flame
• If there is precipitation, it denotes the presence of wither protein or phosphate
• Add 2-4 drops of 2 percent acetic acid
• If precipitate dissolves it is due to phosphates present in normal urine
• If precipitate does not dissolve it denotes presence of albumin

Observation

• Trace: +
• Cloudy:++ (100mg/dL)
• Thick cloudiness: +++ (500 g/dL)

Cold Test

• Pour a small quantity of nitric acid or sulfosalicylic acid 3 percent in to a clean test tube
• Allow equal quantity of urine to trickle down the sides of the test tube
• If albumin present, a white precipitate will be seen where two fluids meet

Urine pH

• Collect and keep ready with urine sample
• Dip litmus strip in urine and keep for one minute
• Note color change
• Discard strip into container for infected waste

Urine Specific Gravity

• Fill 3/4 of jar with urine
• Gently place urinometer into jar
• When urinometer stops bobbing
• Read specific gravity directly from scale marked on calibrated stem of urinometer
• Make sure that instrument floats freely and does not touch sides of jar
• Read scale at lowest point of meniscus to ensure an accurate reading at eye level

Rothera’s Test (Acetone)

• Take 2 cm depth of ammonium sulfate crystals in a small test tube
• Add equal volume of urine and one crystal of sodium nitroprusside
• Close the test tube with a cork and shake the test tube
• Take liquor ammonia and add it to the urine, trickling through the sides
• Read the results immediately

Observations

If acetone is present permanganate purple colored ring is formed at the junction of urine and ammonia

Hays Test (Bile Salts)

• Take a test tube, half full of urine
• Sprinkle sulfur powder on the surface of the urine
• If the powder sinks down to the test tube, it indicates the presence of bile salts

Smith’s Test (Bile Pigments)

• Fill 3/4 of test tube with urine
• Add iodine drops along the sides of the tube, so as to form a layer on the surface of the urine
• A green color at the junction of the two liquids indicates the presence of bile pigments

After Care

• Discard the urine in the sluice room
• Wash the test tube with soap and water
• Dry the tube, holder and urinometer with jar
• Replace the article after cleaning
• Wash hands thoroughly

Record the procedure in the nurse’s record sheet and dietetic chart