10 Preparation AND Handling of Nonblood Specimens PDF

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MEDICAL LABORATORY SCIENCE PROGRAM PRINCIPLES OF MEDICAL LABORATORY SCIENCE PRACTICE 2

Name__________________________________ Points Earned:___________ Section ________________________________ Date ___________________ Learning Activity No. 10 PREPARATION AND HANDLING NONBLOOD SPECIMENS FOR LABORATORY TESTING Learning Outcomes: a. Identify the different nonblood specimens for laboratory testing. b. Describe the various tests performed on the different nonblood specimens. c. Discuss the collection and handling procedures for different nonblood specimens. d. Collect and process sample for urinalysis. Time Allotment: One (1) hour Lecture-demonstration Two (2) hours of actual performance and exercises Learning Resources: Phlebotomy books Clinical Chemistry books Hematology books

NONBLOOD SPECIMENS Routine Urine Urine is the most common sample the patient needs to collect. The laboratory should provide the collection container to ensure cleanliness. For samples that will be used for culture, the container must be sterile. The urine sample can consist of a random sample, first morning or 8-hour sample, double-voided sample, timed sample, or 24-hour sample. All samples except for 24-hour collection are best collected using the clean-catch midstream urine method. At times the sample needs to be collected with catheter by a qualified associate. Collection by a patient is the most common method. Because younger children do not have control of their bladder function, a pediatric urine collection bag is used to collect the urine. This bag adhered to the child, so when he or she urinates, the urine is collected into the bag and can be transferred to a proper screw-top container. The random sample can be collected at any time during a 24-hour period. The patient voids in a collection container at the time the sample is needed. The first morning or 8hour sample is collected when the patient first arises from a night’s sleep. This urine is the most concentrated and represents a sample reflecting the patient’s recumbent position. The 8hour sample is reserved for night workers or individuals who sleep during the day. This still represents a sample that was collected after the patient was 8 hours recumbent. The double voided sample is used to test an analyte at two specific times. The patient collects urine sample and then drinks 200 mL of water. The urine is allowed to accumulate in the bladder for a specified time, and then a second sample is collected. Both samples are tested for analyte, and results are compared. The timed sample is collected at a specific time during a 24-hour period or at a time relative to another activity. This may be done 24 hours after a meal. For certain tests, such as

a urine creatinine clearance test, blood may also be obtained at the same time. All samples over a period of 24 hours must be collected. Certain solutes in the urine exhibit diurnal variations. Catecholamine, 17-hydroxysteroids, and electrolytes are at their lowest concentration in the early morning. They are at their highest at noon or shortly thereafter. For a 24-hour collection of urine, the patient voids and discards the first morning sample. All urine, including the next morning sample, is then saved. The patient must cooperate and not discard a single sample. Refrigeration at 50Celsius will preserve the urine for routine analysis. Chemical preservatives can be used as an alternative for routine urinalysis and in most 24-hour urines that cannot be refrigerated. Semen Collection Semen samples are collected to determine the number and activity of sperm contained in the semen. This can be done as part of a fertility study. It is also required as a post vasectomy sample to determine if the vasectomy was successful. The patient is usually given an instruction sheet and questionnaire to ensure that the best sample is obtained. Post vasectomy samples do not have the critical time constraints that fertility studies have. Post vasectomy samples should be delivered to the laboratory within 2 hours of collection. A post vasectomy sample is checked for the presence or absence of sperm. A sample being tested for fertility must be delivered within 30 minutes due to the rapid deterioration of the sperm and loss of sperm mobility. A sample for fertility testing is checked for the number of sperm, sperm mobility, and sperm abnormalities. Culture Collection A phlebotomist working in a clinic or outpatient setting may be involved in the collection of various types of cultures. Urine cultures are collected in the same manner as a midstream urine collection. The sample container must be sterile for culture to be accurate. The urine sample for culture must be less than an hour old for the most accurate results. If it is impossible to culture the sample within an hour, the sample must be refrigerated. Urine containers are available that eliminate this time variable. The urine is collected by the patient, and then part of the urine is transferred to a special gray-top evacuated tube that contains a preservative. This sample can be cultured several hours later with results consistent with a fresh sample. The phlebotomist also may collect throat cultures or sputum samples for culture. A patient has sore throat, and the physician wants a culture. A swab is used to collect the sample for throat culture. The throat should swabbed with enough force to remove organisms adhering to the throat membrane. Be especially certain to swab any redness, rawness, or white patches for optimum streptococcal isolation. If a rapid strep test is ordered, use two swabs to swab the throat. Nasopharyngeal cultures are cultures of the nasal cavity and pharynx. This is done with a Dacron or cotton-tipped wire swab. The wire on the swab shaft is made to bend so that it can be gently pushed into the nose and then pass into nasopharynx. As the swab is removed it is rotated to collect the sample. Commercial collection sets that contain swabs and transport (holding) media are the collection methods of choice. Sputum Collection Sputum is the mucus and phlegm that a person will cough out from the lungs, bronchi, or trachea. The patient will first complain to the physician about a deep cough with mucus production. This sputum is the sample that will need to be tested for infections or types of body cells being expelled during the coughing episodes. The sample will need to be produced through coughing by the patient and then expectorated into a sterile container. Before collection, the patient will need to rinse the mouth out with water to remove excess food

particles and bacteria. This sample is then maintained at room temperature and tested. Fecal (Stool) Samples Fecal samples are used to help evaluate gastrointestinal disorders. Evaluation for the presence of occult (hidden) blood (guaiac test) is the most common test completed on feces. Special test cards are used for patients to collect feces on the card and the card is then tested in the laboratory. Some of the card test systems require a meat-free diet for at least 3 days before the test. Some newer testing systems do not have diet restrictions and other requirements to handle the feces. Three separate cards are usually collected over 3 different days. Intestinal parasites and their eggs (ova and parasite) can be detected through feces examination. Special containers are provided to the patient. These containers are used to preserve the feces until testing can be completed. The containers may also be used for collection of feces for microbiology culture of feces. Chemistry tests for fats and urobilinogen can be conducted on feces. This testing usually requires at least a 24-hour collection. The sample is collected in metal or plastic paint cans for delivery to the laboratory. Feces collection is often embarrassing for patients. You must be sensitive to their feelings when giving patient instructions. Do the instruction in the privacy of a separate room and not where other patients can hear the conversation. The first question most patients have is how they are going to collect the sample. A large collection bowl sits on the toilet bowl and then the seat of the toilet is lowered to hold the collection bowl in place. The patient will defecate as normal and should make sure the collection bowl is placed back for enough to avoiding getting urine in the sample. Once the sample is obtained, a portion of that sample is placed in the sample container. This is done with a small tongue depressor by spreading some sample on the occult blood reaction area or using the provided scoop device to place some feces into the preservative vials. As soon as the correct amount of sample is obtained, the remaining feces is dumped into the toilet and flushed. The contaminated collection bowl is placed in a trash bag and discarded in the trash. Verify that the sample is properly labeled when the patient returns the feces sample. A. Collecting a Clean-catch Midstream Urine Sample: Male 1. Wash hands using soap and water. 2. Using one of the antiseptic wipes, cleanse the glans (tip) of the penis. Wipe from the urethral opening (orifice), wiping from the opening in a circular motion. If you are not circumcised, this is done while holding the foreskin back. Clean the area around the opening completely. Discard the wipe. Repeat the procedure with a second antiseptic wipe. 3. Following the first cleansing, wipe thoroughly using the second antiseptic wipe, while maintaining the foreskin in a retracted position. Discard the wipe. 4. Void a small amount or urine in the toilet bowl. 5. Continue to void and collect the urine in the cup. Do not touch the sample cup on the inside or touch your body or clothing to it. 6. Place the lid carefully onto the sample container. Screw the lid on tightly to prevent leakage. 7. Give the urine to the laboratory associate.

B. Collecting a Clean-catch Midstream Urine sample: Female 1. 2. 3. 4. 5.

Wash hands using soap and water. Remove underclothing. Sit comfortably on the toilet seat and swing one knee to the side as far as you can. Spread the labia (outer vulva fold) with one hand and continue to keep them apart. Clean the labia. Be sure to cleanse well before you collect the sample. a. Using an antiseptic wipe, clean one side of the fold. Using a separate towelette,...