Chapter 2: Urine Specimen Types Flashcards
The purposes of performing tests using urine are (4)
(1) to aid in the diagnosis of disease;
(2) to screen for asymptomatic, congenital, or hereditary disease;
(3) to monitor disease pro-gression;
(4) to monitor therapy effectiveness or com-plications.
determine the level of a substance in the urine
Quantitative assays
such as assays that measure electrolytes, proteins, hormones, and other metabolic substances (e.g., porphyrins).
Quantitative assays
They are used to detect the presence or increased amount of a substance,
such as rapid pregnancy tests,
tests to detect microbial DNA and RNA (e.g., chlamydia, trichomonas), or a
routine urinalysis
qualitative or screening tests
which provides a real-time “snapshot” of a person’s urinary tract and metabolic status.
routine urinalysis
The most commonly performed urine test is a _______
It is economical and provides valuable patient health information to healthcare providers.
routine urinalysis test
A routine urinalysis evaluates three aspects of the urine:
1) its physical characteristics
2) its chemical composition
3) the microscopic sediment elements (e.g., epithelial cells, blood cells, casts, mucus) suspended in it.
To obtain accurate test results, urine specimen integrity must be maintained. If the urine specimen submitted for testing is inappropriate (e.g., if a random specimen is submitted instead of a timed collection) or if the specimen composition such situations, the highest quality reagents, equipment, exper-tise, and personnel cannot compensate for the unacceptable specimen.
Therefore…(4) must be available to all personnel involved in urine specimen procurement.
written criteria for urine specimen types
instructions for proper collection and preservation
appropriate specimen labeling, and a
handling timeline
______ is actually a “fluid biopsy” of the kidneys and can provide a fountain of information about the health of an individual
Urine
The____ are the only organs that can have their functional status evaluated by such a noninvasive means.
.
kidneys
In addition, because______ is an ultrafiltrate of the plasma, it can be used to evaluate and monitor body homeostasis and many metabolic disease processes
urine
(3) are usually determined by the tests to be performed.
The type of specimen selected
the time of collection, and
the collection technique
The three basic types of urine specimens are
first morning
random
timed collections
Specimen type: Random
Description
Uses
• Urine collected at any time
• Routine screening
• Cytology studies (with prior hydration)
• Fluid deprivation tests
Specimen type: First morning
Description
Uses
• First urine voided after sleep (~6-8 hr)
• Most concentrated urine
• Routine screening; good recovery of cells and casts
• To confirm postural or Orthostatic proteinuria
• Cytology studies
Specimen type: Timed
Description
Uses
• Collect all urine during a specific timed interval (e.g., 24-hr,
12-hr, 2-hr)
• Preservatives and/or refrigeration during collection may be required
• Quantitative chemical analysis
• Clearance tests
• Cytology studies
• Evaluation of fistula
To collect a______, the patient voids before going to bed and immediately on rising from sleep collects a urine specimen.
first morning specimen
Because this urine specimen has been retained in the bladder for approximately 8 hours, the specimen is ideal to test for substances that require concentration or incubation for detection (e.g., nitrites, protein) and to confirm postural or orthostatic proteinuria.
first morning specimen
Formed elements such as white blood cells, red blood cells, and casts are more stable in these concentrated acidic urine specimens.
First morning specimen
Because the number of epithelial cells present can be significant, these specimens may be used for cytology stud-ies.
First morning specimen
The high osmolality of ________specimens maintains the morphology of cellular components and reduces degeneration of renal casts.
However, the high concentration of salts in these specimens can crystallize on cooling to room temperature (e.g.,_____) and interfere with routine processing for cytologic studies.
first morning
amorphous urates
Although the_______ is usually the most concentrated and is frequently the specimen of choice, it is not the most convenient to obtain.
It requires that the patient pick up a container and instructions at least 1 day before his or her appointment; in addition, the specimen must be preserved if it is not going to be analyzed within____ of collection.
first morning urine
2 hours
For ease and convenience, routine screening is most often performed on________
random urine specimens
can be collected at any time, usually during daytime hours and without prior patient preparation.
random urine specimens
Because excessive fluid intake and strenuous exercise can directly affect urine composition, _______may not accurately reflect a patient’s condition.
Despite this, ____ specimens are usually satisfactory for routine screening and are capable of detecting abnormalities that indicate a disease process.
random urine specimens
With prior hydration of the patient, a random clean catch urine specimen is ideal for_______.
Hydration consists of instructing the patient to drink________ of water each hour for _____before urine collection.
Most cytology protocols require collection of these specimens daily for _____consecutive days. This increases the number of cells studied, thereby enhancing the detection of abnormality or disease.
cytology studies
24 to 32 ounces, 2 hours
3 to 5
Random urine specimen
One method that can be used to increase the cellularity of a urine specimen is to have the patient…… before specimen collection.
exercise for 5 minutes by skipping or jumping up and down
Because of circadian or diurnal variation in excretion of many substances and functions (e.g., hormones, proteins, glomerular filtration rate) and the effects of exercise, hydration, and body metabolism on excretion rates, quantitative urine assays often require a_______
timed collection
_______, usually 12-hour or 24-hour, eliminate the need to determine when excretion is optimal and allow comparison of excretion patterns from day to day.
Timed collections
Timed urine specimens can be divided into two types:
those collected for a predetermined length of time (e.g., 2hours, 12hours, 24hours)
those collected during a specific time of day (e.g., 2 PM to 4PM).
4-hour or 12-hour specimen for determination of urine albumin, creatinine, and the albumin-to-creatinine ratio can be collected anytime and is an ideal specimen to screen for________.
microalbuminuria
2-hour collection for determination of________ is preferably collected from 2PM to 4PM the time when maximal excretion of urobi-linogen is known to occur (in most individuals).
urinary urobilinogen
Timed collection
A rule of thumb is to…
- Empty your bladder and discard that urine at the start.
- Collect all urine you pass during the collection period.
- At the end, empty your bladder again and include that urine in the collection.
Timed collection
Depending on the analyte being measured, a ______may be necessary to ensure its stability throughout the collection.
urine preservative
Timed collection
Depending on the analyte being measured, a ______may be necessary to ensure its stability throughout the collection.
urine preservative
Timed collection
In addition, certain foods and drugs can affect the urinary excretion of some analytes.
When this influence is known to be significant, the patient needs to be properly instructed to avoid these substances.
Written instructions should include: (3)
the test name
the preservative required
any special instructions or precautions
Timed collection
The most common errors encountered in quantitative urine tests are related directly to specimen collection or handling, such as (5)
loss of specimen (i.e., not collecting all urine excreted in a timed col-lection)
inclusion of two first morning samples
inaccurate total volume measurement
transcription error
inadequate preservation
