URINE COMPOSITION, COLLECTION, AND PRESERVATION Flashcards
URINE COMPOSITION
[?] water
[?] solutes (~60 grams of total solids in 24 hours)
95-97%
3-5%
Influenced by dietary intake, physical activity, body metabolism, endocrine functions and even body position
URINE
INORGANIC COMPONENTS
Chloride > Sodium > Potassium
NaCl
Others: sulfate, phosphate, ammonium, magnesium, calcium
principal salt
NaCl
major INORGANIC COMPONENT
Chloride
ORGANIC COMPONENTS
Urea
Uric acid
Hippuric acid
Creatinine
Others: carbohydrates, pigments, fatty acids, mucin, enzymes, hormones
(60 to 90%): major organic component
Urea
Containers
- clean, dry, leak-proof, clear
- Disposable
- wide-mouthed with a secure lid, and a wide, flat bottom
Labels
- patient’s name and identification number
- Date and time of collection
Requisitions
- Information on the form must match the information on the [?]
- [?] the specimen is received in the laboratory
specimen label
time
Urine container capacity
- 50 ml capacity
Specimen Rejection
- [?] labeled specimens
- Nonmatching labels and [?]
- Specimens contaminated with [?]
- containers with [?] exteriors
- Specimens with [?] quantity
- Specimens that have been [?]
Unlabeled or improperly
requisition forms
feces or toilet paper
contaminated
insufficient
improperly transported
Specimen Integrity
within 2 hours
Physical, chemical and microscopic characteristics of urine specimen begin to change as soon as the urine is
voided
Specimen Preservation: Increased
- pH
- Bacteria
- Odor
- Nitrite
Specimen Preservation: Decreased
- Clarity
- Glucose
- Ketones
- Conjugated bilirubin
Specimen Preservation: Modified
Color
Urea——(urease)—- > Ammonia
Increased pH
Increased Odor
Multiplication
Increased Nitrite (nitrate-reducing bacteria)
Increased Bacteria
Decreased Clarity
Precipitation of amorphous materials
Clarity
Glycolysis and bacterial use
Decreased
Volatilization
Decreased Ketones
Light exposure
Decreased Conjugated bilirubin
Oxidation or reduction of metabolites
Modified Color
Oxidation to urobilin
Decreased Urobilinogen
Disintegrates in ALKALINE urine
Decreased Casts
Loss of motility: death
Decreased Trichomonas
TYPES OR PRESERVATION
- PHYSICAL
- CHEMICAL
REFRIGERATION
PHYSICAL PRESERVATION
↓ Bacterial growth and metabolism
↑ Specific gravity
REFRIGERATION
Precipitation of Amorphous phosphates and urates
REFRIGERATION
REFRIGERATION TEMP
2C - 8C
Does not interfere with chemical tests
Refrigeration
Increases SG by hydrometer
Refrigeration
Precipitates amorphous substances
Refrigeration
Prevents bacterial growth for 24 hours
Refrigeration
Preserves glucose and sediments well
Thymol
Interferes with acid precipitation test for CHONS
Thymol
Preserves CHONS and formed elements well
Boric acid
Does not interfere with routine analyses other than pH
Boric acid
May precipitate crystals when used in large amounts
Boric acid
Keeps pH about 6.0
Boric acid
Bacteriostatic at 18g/L; may be used for culture transport
Boric acid
Excellent sediment preservative
Formaldehyde
Reducing agent, interferes with chemical tests for glucose, blood, LE, and Copper reduction
Formaldehyde
Rinse specimen container with formalin to preserve
Formaldehyde
Does not interfere with routine tests
Toluene
Floats on urine surface; clings to glass wares
Toluene
Prevents glycolysis; good preservative for drug analysis
NaF
Inhibits reagent strip tests for glucose, blood and leukocytes
NaF
May use Na benzoate instead of fluoride for reagent strip testing
NaF
Does not interfere with routine tests
Phenol
Causes odor change
Phenol
Use 1 drop per ounce of specimen
Phenol
Preserves cellular elements
Saccomanno (50% ethanol + 2% carbowax)
Used for cytology studies (50 mL urine)
Saccomanno (50% ethanol + 2% carbowax)
Convenient when refrigeration is not possible
Commercial tablet preservatives
May contain one or more of the preservatives including NaF
Commercial tablet preservatives
Check tablet composition to determine possible effects on desired test
Commercial tablet preservatives
Contains collection cup, C&S preservative tube or UA tube
Urine Collection Kits
Sample stable @ RT for 48 hrs; bacteriostatic
Gray C&S tube
Decreases pH; do not use if urine is below min fill line
Gray C&S tube
Boric acid is the preservative and may not be used for UA
Gray C&S tube
Used on automated instruments
Yellow plain UA tube
Must refrigerate within 2 hours
Yellow plain UA tube
Round/conical bottom
Yellow plain UA tube
Stable for 72 hours at RT; instrument compatible
Cherry red/yellow top tube
Bilirubin and urobilinogen may be decreased if specimen is exposed to light and left at RT
Cherry red/yellow top tube
Na propionate is the preservative
Cherry red/yellow top tube
METHODS OF URINE COLLECTION
- Bottle Method
- Plastic Bag with Adhesive
- Urethral Catheterization
- Suprapubic Aspiration
most-commonly used method; performed via midstream clean catch
- Bottle Method
for pediatric patients
- Plastic Bag with Adhesive
catheter is inserted up to the urinary bladder or ureter
- Urethral Catheterization
collected via external introduction of a needle through the abdomen and into the bladder
- Suprapubic Aspiration
Routine screening
Random specimen
First Morning Specimen
Midstream CleanCatch Specimen
Pregnancy tests
First Morning Specimen
Orthostatic protein
First Morning Specimen
Diabetic screening/monitoring
Second Morning Specimen (Fasting Specimen)
2-hour Post Prandial Specimen
Urobilinogen testing
Afternoon specimen
Early Afternoon specimen (2-4pm)
Addis Count (Sediments)
12-hour urine sample
Quantitative chemical tests
24- hour (Timed) Specimen
Accompaniment to blood samples in glucose tolerance test
Glucose Tolerance Specimen
Bacterial culture
Catheterized Sample
Midstream CleanCatch Specimen
Suprapubic Aspiration
Cytology
Suprapubic Aspiration
Prostatic infection
3- glass collection
- Ideal specimen for routine UA and Pregnancy test
First Morning Specimen
- Concentrated, most acidic: for well preservation of casts
First Morning Specimen
- For evaluation of Orthostatic Proteinuria
First Morning Specimen
- 2nd voided urine after a period of fasting
Second Morning Specimen (Fasting Specimen)
- For Nitrite determination
4-hour urine
- Urine remains in the bladder for at least 4 hours before voiding
4-hour urine
By Thomas Addis(1926)
Addis count
Quantitates formed elements in a 12-hour overnight urine collection
Addis count
used primarily to monitor the course of diagnosed cases of renal disease
Addis count
Addis count
Casts:
RBC:
WBC:
Casts: >5, 000
RBC: >500, 000
WBC: >2,000,000
First specimen voided.
First Morning Specimen
Most ideal specimen for screening/ testing
First Morning Specimen
Most concentrated specimen.
First Morning Specimen
Essential specimen for pregnancy test and orthostatic/ lordotic proteinuria
First Morning Specimen
Second voided specimen after a period of fasting.
Second Morning Specimen (Fasting Specimen)
Best specimen for glucose monitoring.
Second Morning Specimen (Fasting Specimen)
Specimen collected after 2 hours of eating.
2-hour Post Prandial Specimen
Specimen used for monitoring insulin therapy in patients with DM.
2-hour Post Prandial Specimen
Glucose result from this specimen is compared with 2PPBS.
2-hour Post Prandial Specimen
Begins and ends with an empty bladder; requires preservative depending on the test to be performed
24- hour (Timed) Specimen
Most commonly requested for urine specimen for bacterial culture.
Catheterized Sample
Used to measure functions in the individual kidneys
Catheterized Sample
Safer, less traumatic specimen that is suitable for routine urinalysis and bacterial culture.
Midstream CleanCatch Specimen
Females: separate the skin folds
Midstream CleanCatch Specimen
Collected directly from the urinary bladder.
Suprapubic Aspiration
For bacterial bladder urine culture.
Suprapubic Aspiration
Also used for cytologic examination
Suprapubic Aspiration
Specimen used for the detection of prostatic infection.
3- glass collection
1st glass sample-
- first urine passed
2nd glass sample-
- midstream portion
3rd glass sample-
- prostate massage, remaining urine
Urine after prostatic massage
Examine the 1st and 3rd specimen microscopically, then compare the number of WBC and bacteria
3- glass collection
in the number of WBC and bacteria in the 3rd specimen is 10x greater than that of the 1st specimen
Prostatic Infection=
= CONTROL for bladder and kidney infection. If (+) for WBCs and bacteria, the result from the 3rd specimen is INVALID
2nd Specimen
-tested for urethral infection or inflammation
VB1
-tested for urinary bladder infection
VB2
- cultured and examined for white blood cells(>10-20 WBCs/HPF is considered abnormal)
EPS
- postprostatic massage urine specimen
VB3
Clean-catch midstream urine is collected
PPMT(PRE AND POSTMASAGE TEST)
Second urine is collected after the prostate is massaged
PPMT(PRE AND POSTMASAGE TEST)
Positive result: >10 x the premassage count
PPMT (PRE AND POSTMASAGE TEST)
Specimen collected from pediatric patients.
Pediatric Specimen
Uses weebag, a soft, clear plastic bag with adhesive, for collection.
Pediatric Specimen
soft, clear plastic bags with hypoallergenic skin adhesive to attach to the genital area of both boys and girls
Pediatric Specimen
: process that provides documentation of proper sample identification from the time of collection to the receipt of laboratory results.
- Chain of Custody
- Required volume: 30-45 ml
Drug Specimen
Drug Specimen
- Temperature (within 4 minutes):
Drug Specimen
32.5-37.7°C
- Bluing agent is added to the toilet water reservoir to prevent specimen adulteration
Drug Specimen
- At least 2 voided collection
Fractional Specimen
- Series of blood and urine samples are collected at specific time intervals to compare concentration of a substance in urine with its concentration in the blood (diagnosis of diabetes)
Fractional Specimen
Specimens collected anytime of the day
Random specimen
Most commonly received specimen in the laboratory.
Random specimen
Useful for routine screening tests to detect obvious abnormality
Random specimen
It is the total daily urine output.
24- hour (Timed) Specimen
Used for quantitative urine testing.
24- hour (Timed) Specimen
Begins and ends with an empty bladder
24- hour (Timed) Specimen
If placed in 2 containers, mixed the urine samples well first before aliquoting
24- hour (Timed) Specimen
Urine Creatinine determination
24- hour (Timed) Specimen
4-aminobenzoic acid (gold standard)
24- hour (Timed) Specimen
24- hour (Timed) Specimen
o Adult -
o Less than 1 year old -
o 1 to 14 years old -
600-2000 mL/ 24 hours
100-500 mL/ 24 hours
500-1400 mL/ 24 hours
Specimen for used to check for the ability of the kidney to metabolize a measured amount of glucose.
Correlated with renal threshold.
side by side specimen with OGTT.
Glucose Tolerance Specimen
