Download Chapter 30 - Bakersfield College

Chapter 30
Collecting and Testing Specimens
LEARNING OUTCOMES:
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Define the key terms and key abbreviations listed in this chapter
Explain why urine, stool sputum, and blood specimens are collected
Explain the rules for collecting specimens
Describe the different types of urine specimens
Describe the equipment used for blood glucose testing
Identify the sites used for skin punctures
Perform the procedures described in this chapter
Specimens (samples) are collected and tested to prevent, detect,
The doctor orders what specimen to collect and the test needed.
Most specimens are tested in the laboratory.
and treat disease.
•All specimens sent to the laboratory require requisition slips.
Some tests are done at the bedside.
URINE
SPECIMENS
The random urine specimen
•The random urine specimen is collected for a routine urinalysis.
•It is collected any time during a 24-hour period.
The
midstream specimen (clean-voided specimen or clean-catch specimen)
•The perineal area is cleaned before collecting the specimen.
•To collect the specimen:
The person starts to void into a receptacle.
The person stops the stream of urine.
A sterile specimen container is positioned.
The person voids into the container until the specimen is obtained.
The
24-hour urine specimen
•All urine voided during a 24-hour period is collected.
•Urine is chilled on ice or refrigerated during this time.
•A preservative is added to the collection container for some tests.
•The person voids to begin the test with an empty bladder.
Discard this voiding.
Save all voidings for the next 24 hours.
•The test is restarted if:
A voiding was not saved
Toilet tissue was discarded into the specimen
The specimen contains feces
The
double-voided specimen (fresh-fractional urine specimen)
•The person voids twice.
The first time the bladder is emptied of “stale” urine.
In 30 minutes, the person voids again.
•Fresh-fractional urine specimens are used to test urine for glucose and ketones.
To collect a urine specimen from an infant or a child who is not toilet-trained, a
collection bag (“wee bag”) is applied over the urethra.
Testing
urine
•Testing for pH
Urine pH measures whether urine is acidic or alkaline.
A routine urine specimen is needed.
•Testing for glucose and ketones
The diabetic person may have sugar (glucose) in the urine.
The diabetic person may also have acetone (ketone bodies, ketones) in the urine.
Urine is tested for glucose and ketones.
The doctor uses the test to make drug and diet decisions.
Double-voided specimens are best for these tests.
•Testing for blood
Injury and disease can cause hematuria (blood in the urine).
Sometimes blood is seen in the urine.
At other times, it is unseen (occult).
A routine urine specimen is needed.
•Using reagent strips
Do not touch the test area on the strip.
Dip the strip into urine.
Compare the strip with the color chart on the bottle.
•A stone (calculus) can develop in the kidney, ureter, or bladder.
Stones (calculi) vary in size.
Stones causing severe pain and urinary system damage may require surgical removal.
Some stones are passed through urine.
–All of the person’s urine is strained.
–Passed stones are sent to the laboratory.
STOOL
SPECIMENS
Stools are checked and studied for blood, fat, microbes, worms, and other abnormal
contents.
The stool specimen must not be contaminated with urine.
Some tests require a warm stool.
Testing
stools for blood
•Stools may contain blood for many reasons.
•Often blood is seen if it is low in the bowels.
•Stools are black and tarry (melena) if there is bleeding in the stomach or upper
gastrointestinal tract.
•Sometimes bleeding occurs in very small amounts and cannot be seen (occult blood).
•When using occult blood test kits, follow the manufacturer’s instructions.
SPUTUM
SPECIMENS
Mucus from the respiratory system is called sputum when expectorated (expelled)
through the mouth.
•Sputum is not saliva.
Sputum specimens are studied for blood, microbes, and abnormal cells.
The person coughs up sputum from the bronchi and trachea.
•It is easier to collect a specimen in the morning.
BLOOD
GLUCOSE TESTING
Blood glucose testing is used for persons with diabetes.
•The doctor uses the results to regulate the person’s drugs and diet.
Capillary blood is obtained through a skin puncture.
•A fingertip is the most common site for skin punctures.
•The earlobe also is a site.
To
perform a skin puncture:
•Inspect the site carefully.
Look for signs of trauma and skin breaks.
Avoid sites that are swollen, bruised, cyanotic, scarred, or calloused.
•Do not use the center, fleshy part of the fingertip.
•Use the side toward the tip of the fingertip on the middle or ring finger.
•A sterile lancet is used to puncture the skin.
A glucose meter (glucometer) is used to measure blood glucose.
Many different glucose meters are available.
•Follow the manufacturer’s instructions.