Y khoa, dược - Collecting, processing, and testing urine specimens

47Collecting, Processing, and Testing Urine Specimens47-2Learning Outcomes47.1 Describe the characteristics of urine, including its formation, physical composition, and chemical properties.47.2 Explain how to instruct patients in specimen collection.47.3 Identify guidelines to follow when collecting urine specimens.47.4 Describe proper procedures for collecting various urine specimens. 47-3Learning Outcomes (cont.)47.5 Explain the process of urinary catheterization.47.6 List special considerations that may require you to alter guidelines when collecting urine specimens.47.7 Explain how to maintain the chain of custody when processing urine specimens.47.8 Explain how to preserve and store urine specimens. 47-4Learning Outcomes (cont.)47.9 Describe the process of urinalysis and its purpose. 47.10 Identify the physical characteristics present in normal urine specimens.47.11 Identify the chemicals that may be found in urine specimens.47.12 Identify the elements categorized and counted as a result of microscopic examination of urine specimens. 47-5IntroductionRoutine analysis of a urine specimenNoninvasive Used to diagnose significant conditionsMedical assistantLearn about types of urine specimensInstruct or assist patient in collection of a sampleLearn to process urine specimensLearn about normal/abnormal components of urine 47-6Role of the Medical AssistantCollect, process, and test urine samplesKnowledge necessaryAnatomy and physiology of kidneysHow urine is formedNormal components of urine47-7Role of the Medical AssistantSafetyStandard PrecautionsPPE as neededHandle and dispose of specimens properlyDispose of used supplies and equipment properlySanitize, disinfect, and/or sterilize reusable equipment47-8Anatomy and Physiology of the Urinary SystemOrgansKidneys – remove excess water and waste productsUreters – drain urine into bladderBladder – stores urineUrethra – drains urine to outside of the body47-9Formation of UrineNephron Functional unit of the kidneyRemoves end products of metabolismAllows for reabsorption of water and electrolytesMaintains normal fluid balanceProcesses in urine formationGlomerular filtrationTubular reabsorptionTubular secretion47-10Physical Composition and Chemical Properties of Urine95% water5% waste productsOther dissolved chemicalsUreaUric acidAmmoniaCalciumCreatinineSodiumChloridePotassiumSulfatesPhosphatesHydrogen ionsUrochromeUrobilinogenA few RBCsA few WBCs47-11Apply Your KnowledgeWhat knowledge is needed by the medical assistant related to collecting, processing, and testing urine specimens? ANSWER: The medical assistant needs to know the anatomy and physiology of the urinary system, how urine is formed, and normal components of urine.Components of normal urine includeA. urea, uric acid, and ammonia.B. chloride, potassium, and sugar.C. red blood cells, sperm, and H2O2D. hydrogen ions, urochrome, and  uranium.ANSWER:Very Good!47-12Obtaining Specimens General collection guidelinesFollow the procedure for specified testUse an appropriate specimen container Label the specimen container correctlyExplain the procedure to patientWash your hands before and after the procedure; wear gloves during the procedureComplete all necessary paperwork47-13Specimen TypesQuantitative analysis – measuresamount of a specific substance in the urineQualitative analysis – simplydetermines if a substance ispresent in the urineTypes vary in the method used to collect a specimen and in the time frame in which to collect a specimen47-14Specimen Types (cont.)Random urine specimenMost commonObtained any time during the dayFirst morning specimenContains greater concentration of substancesClean-catch midstreamUsed for culturing urineExternal genitalia must be cleansedDiscard small amount of urine prior to collecting specimenCan also obtain by catheterization47-15Specimen Types (cont.)Timed urine specimenDiscard first specimenCollect all urine for specified timeRefrigerate 24-hour specimenCollected as a timed specimenBoth are used for qualitative and quantitative analysis47-16CatheterizationUrinary catheter – a plastic tube inserted to provide urinary drainageCatheterization – procedure by which the catheter is inserted47-17Catheterization (cont.)Reasons for catheterizationRelieve urinary retentionObtain a sterile urine specimenMeasure the amount of residual urine Obtain a specimen if patient cannot voidInstill chemotherapyEmpty bladder before and during procedures47-18Catheterization (cont.)Drainage cathetersIndwelling urethral (Foley) catheter – bladder Retention catheter – renal pelvisUreteral catheter – drainage through a wound into the bladder (cystostomy tube)Straight catheter – bladderSplinting catheter – inserted after repair of ureter 47-19Catheterization (cont.)Not a routine procedure due to risk of infectionNot typically performed by medical assistantsCheck scope of practiceAssemble supplies – catheterization kits47-20Special ConsiderationsMale and female patientsDifferences in collecting clean-catch midstream specimenQuestions during historyPregnant patientsFrequencyProne to urinary tract infectionUrine checked for glucose and protein47-21Special Considerations (cont.)ElderlyBladder muscles weakenUterine supports weaken – pulls on bladderLoss of bladder controlMay need assistance in obtaining a specimenRepeat explanation as necessaryPediatric patientsInvolve child if possibleQuestionsDiaper rash?Excessively thirsty?Difficulty urinating?Cry when urinating?How many diapers a day?Change in bladder control?Problems toilet training?47-22Establishing Chain of CustodyDo not alter established procedurePositively identify patientExplain procedure and have patient sign a consent formExamine specimen and check temperatureComplete documentation47-23Preservation and StorageChemical, physical, and microscopic changes occur if urine is left at room temperature for more than 1 hourPreservationRefrigeration Prevents growth for 24 hoursReturn to room temperature before testingChemical preservatives Specimens only47-24Apply Your KnowledgeA patient has returned to the office and is complaining of not being able to empty her bladder fully after her hysterectomy. The physician has asked you measure the patient’s residual urine. How do you do this and why?ANSWER: A residual urine is done to measure the amount of urine in the bladder after voiding. You will ask the patient to empty her bladder and then perform a straight catheterization to measure any urine remaining in her bladder.Correct!47-25UrinalysisEvaluation of urine to obtain information about body health and diseaseTypes of testingPhysicalChemicalMicroscopic47-26Urinalysis (cont.)Values Negative or none, normal, or a range of concentrationWithin normal limits indicate health and normalityScreening test – must havefollow-up testing47-27Urinalysis (cont.)Average adult daily urine output is 1250 mL/24 hoursIntake and output should be approximately the sameDysfunctions of other body systems can affect urinary function47-28Physical Examination and Testing of Urine SpecimensCheck labelCheck for visible contaminationCheck time since collectionVisual examinationColor Volume NormalOliguria OdorSpecific gravity47-29Physical Examination and Testing of Urine Specimens (cont.)Visual examinationColor/turbidity – pale yellow to dark amber; clearVolume Normal range – 600–1800 mL/24 hoursOliguria – insufficient production of urineAnuria – absence of urine production47-30Physical Examination and Testing of Urine Specimens (cont.)OdorDistinct, aromaticStanding at room temperature – ammoniaAffected by disease and foodsSpecific gravity1.002 to 1.028Fluctuates in response to fluid intakeMethods Refractometer Reagent strips47-31Chemical Testing of Urine SpecimensCheck label on specimenDetermine the status of Carbohydrate metabolismLiver or kidney functionAcid-base balancePresence of drugs, toxins, or infectionsReagent strip testingChanges indicate presence of concentration of a substanceFollow instructions carefully47-32Chemical Testing of Urine Specimens (cont.)Ketone bodies Normally none in urinePresencePatient on a low-carbohydrate dietStarvationExcessive vomitingDiabetes mellituspHNormal 5.0 to 8.0Alkaline UTIMetabolic/ respiratory alkalosisAcidic PhenylketonuriaAcidosis 47-33Chemical Testing of Urine Specimens (cont.)BloodHematuria Menstruation InfectionTraumaHemoglobinuria – free hemoglobin in urineMyoglobinuria Myoglobin in urineInjured or damaged muscles BilirubinFrom the breakdown of hemoglobinBilirubinuria – early sign of liver diseaseUrobilinogen Elevated – increased RBC destructionLacking – bile duct obstruction47-34Chemical Testing of Urine Specimens (cont.)GlucoseNormally in small amountsGlycosuria – diabetes ProteinExcess – renal disease Proteinuria – common in pregnancy and after heavy exercise47-35Chemical Testing of Urine Specimens (cont.)Nitrite – suggests bacterial infectionLeukocytes – urinary tract or renal infectionPhenylketonesPresence indicates phenylketonuria (PKU) – genetic disorderBlood testing is more routine for newborns47-36Chemical Testing of Urine Specimens (cont.)Pregnancy testDetect human chorionic gonadotropin (HCG)Peak at 8 weeksQuick, easy to perform and interpretEnzyme immunoassay (EIA)Newer technologyAntigen/antibody reaction47-37Chemical Testing of Urine Specimens (cont.)Presence of STDsScreening for chlamydia – 15- to 25-year-old sexually active femalesNucleic acid amplification tests (NAATs)Detect nucleic acid in urineChlamydia and gonorrhea Advantage – highly specific, non-invasiveDisadvantage – expensive, no organism remains for culture47-38Microscopic Examination of Urine SpecimensView elements only visible with microscopeCentrifuge Obtain sedimentSpins fluid – heavier substances settle to the bottom of the tubes47-39Microscopic Examination of Urine Specimens (cont.)Cells Epithelial cellsWhite blood cellsRed blood cellsCasts Cylindrical elementsTypesHyaline GranularRBC castsWBC castsEpithelial cell castsWaxy47-40Microscopic Examination of Urine Specimens (cont.)Crystals Naturally produced solids of definite formCommon in urineDetermine pH before testingYeast cellsMay be confused with RBCsAssociated with genitourinary tract infection, diabetes47-41Microscopic Examination of Urine Specimens (cont.)Bacteria A few are normalInfection if urine also hasPutrid odorWBCsParasitesInfection or contaminationTrichomonas vaginalis – most common47-42Apply Your KnowledgeWhat is the specific gravity shown on this refractometer screen?ANSWER: The specific gravity shown here is 1.030.47-43Apply Your KnowledgeA urinalysis has detected that a patient has protein in his urine. Why is this important?ANSWER: Protein in the urine usually indicates renal disease.Super!47-44In Summary47.1 Urine is formed during a filtration process that occurs in the nephron. It is made up of 95% water and 5% waste products and other dissolved chemicals, including urea, uric acid, ammonia, calcium, creatinine, sodium, chloride, potassium, sulfates, phosphates, bicarbonates, hydrogen ions, urochrome, urobilinogen, a few red blood cells, and a few white blood cells.47-45In Summary (cont.)47.2 Instructions for obtaining specific types of specimens will vary according to the test. The general instructions for urine specimen collection are: urinate into the container indicated by the laboratory; if the collection container contains liquid or powdered preservative, do not pour it out; always refrigerate the labeled collection container or keep it in a cooler or pail filled with ice; be sure to keep the lid on the container.47-46In Summary (cont.)47.3 The general guidelines for collecting a urine specimen include: follow the procedure that is specified for the urine test that will be performed; use the type of specimen container indicated by the laboratory; properly label the specimen container; explain the procedure to the patient when assisting in the collection process; wash your hands before and after the procedure and wear gloves during the procedure; and complete all necessary paperwork.47-47In Summary (cont.)47.4 Several types of urine specimens are collected in the medical office. Each specimen has a slightly different collection method. The various specimens include random, first morning, clean-catch midstream, timed, and 24-hour.47.5 Urinary catheterization involves inserting a plastic drainage tube into the kidney, the ureter, or the bladder.47.6 When the medical assistant obtains a urine specimen from a patient or takes a history of a patient who may have a urinary problem, she or he needs to consider the patient’s sex, condition, and age. 47-48In Summary (cont.)47.7 When collecting a chain-of-custody specimen, the following safeguards should be used: positively identify the donor; have the donor remove outer clothing and empty pockets, displaying all items; add bluing agent to the water in the toilet and turn off other water sources; remain by the door while the specimen is being obtained; measure and record the temperature of the specimen within four minutes; have the donor witness the specimen transfer; complete additional information on the form; sign the CCF; give a copy of the CCF to the donor; place the specimen in a leak-proof bag with a copy of the form; and release the specimen to the courier service.47-49In Summary (cont.)47.8 Proper preservation and storage of specimens are essential. A specimen should not be left unpreserved for more than 1 hour. Refrigerate a specimen if it cannot be tested within an hour. Bring the specimen back to room temperature before testing.47.9 Urinalysis is the evaluation of urine by various types of testing methods to obtain information about body health and disease.47-50In Summary (cont.)47.10 The physical characteristics of normal urine include color and turbidity, volume, odor, and specific gravity. 47.11 The chemicals that may be found in urine specimens include ketones, nitrite, bilirubin, glucose, and protein.47.12 During microscopic urine examination, elements that are categorized and counted include the cells, casts, crystals, yeast, bacteria, and parasites.47-51End of Chapter 47A human being: an ingenious assembly of portable plumbing. ~ Christopher Morley, 1890-1957