Presentation on theme: "Pre-analytical Laboratory Errors"— Presentation transcript:
1Pre-analytical Laboratory Errors Tim Guirl MT (ASCP)Phlebotomy InstructorNorth Seattle Community CollegeHealth & Human Services Division
2ObjectivesIdentify the significant pre-analytical errors that can occur during blood specimen collection and transportExplain the various means of pre-analytical error preventionList proactive steps to reduce potential pre-analytical errors associated with blood collection and transport
3IntroductionThree phases of laboratory testing: pre-analytical, analytical and post-analyticalPre-analytical—specimen collection, transport and processingAnalytical—testingPost-analytical—testing results transmission, interpretation, follow-up, retesting.
4Phlebotomy ErrorsPhlebotomy is a highly complex skill requiring expert knowledge, dexterity and critical judgmentIt is estimated that one billion venipunctures are performed annually in the U.S.Phlebotomy errors may cause harm to patients or result in needlestick injury to the phlebotomist
5Pre-analytical errors Pre- and post-analytical errors are estimated to constitute 90% of errorsErrors at any stage of the collection, testing and reporting process can potentially lead to a serious patient misdiagnosisErrors during the collection process are not inevitable and can be prevented with a diligent application of quality control, continuing education and effective collection systems
7Patient Identification Errors Errors in correctly identifying the patient are indefensibleReasons for patient identification errorsProper positive patient identification procedures not followedPatient identification from identification bracelet (inpatients)Patient identification by asking patients to state or spell their full name (inpatients/outpatients)Patient identification by staff or family member if patient unable to identify him/herself
8Patient Identification Errors Specimen tubes unlabeledRequisition or collection tube labels not affixed to tubesRequisition or collection tube labels in bag containing collection tubesRequisition or collection tube labels rubber-banded to tubesCollection tube labels not affixed to all tubesSpecimen collection tubes labeled insufficiently with at minimum patient’s full name, date/time of collection, phlebotomist’s initials
9Patient Identification Errors Collection tubes labeled with the wrong patientWrong computerized labels affixed to collection tubes at bedsideCollection tubes not labeled at the time of collectionCollection tubes incorrectly labeled by someone other than the phlebotomist who collects the specimen
10Patient Complications Some patient variables that affect blood specimensDietFastingExerciseObesityAllergies to alcohol or iodine used to clean venipuncture siteUse alternative cleanser such as chlorhexidine
11Phlebotomy Technique Errors Phlebotomy technique is importantEnsures test result validityMinimizes trauma to patientMinimizes potential for phlebotomist injuryReduces recollectionsVein selection essential for successful venipunctureThree veins in antecubital fossa in order of selection (1) median cubital (2) cephalic (3) basilic
12Phlebotomy Technique Errors Site SelectionAvoid sites with IVUse alternative arm or draw below IV to avoid contamination/dilution from IVDocument arm if IVMastectomy—avoid site due to lymphostasisInfection risk/alteration in body fluids and blood analytesEdematous areas —avoid due to accumulation of body fluidsPossible contamination/dilution of specimen
13Phlebotomy Technique Errors Venous Access DifficultiesObstructed, hardened, scarred veinsVeins difficult to locateUse of Alternative sitesTop of hand/Side of wristAreas to avoidVein CollapseUse of appropriate needle sizeSmaller evacuated collection tube
14Phlebotomy Technique Errors Tourniquet ApplicationTourniquet tied too close to the venipuncture site can cause hematomaVeins may not become prominent if tourniquet is tied too high (more than 3 to 4 inches above venipuncture site)Tourniquet left on longer than one minute can result in hemoconcentration, affecting some test resultsTourniquet should be released as soon as needle is in the lumen of the vein and blood flow established
15Phlebotomy Technique Errors Cleansing of venipuncture siteThorough cleaning with alcoholAllow alcohol to dry completely to avoid stinging sensation upon needle entry and hemolysis of sampleSamples such as blood cultures should be collected using iodine to cleanse site to ensure sterility of sampleRecollection rate for blood cultures ranges due to contamination is as high as 50% in hospitals with increased costs, patient overtreatment
16Phlebotomy Technique Errors Correct collection systemEvacuated tube system (Vacutainer) for large veins in antecubital fossaSyringe for small, fragile veins or veins outside antecubital fossaVenous accessNeedle entry should be at 15 to 30 degrees depending on depth of veinNeedle entry should be in same direction as vein, centered over veinAnchor vein to prevent movement during needle entry and to reduce pain to patient
17Test Collection Errors Order of DrawOrder of draw affects the quality of the sample and can lead to erroneous test results due to contamination with the additive from the previous blood collection tubeHemolysisBlood collected insufficient to amount of additive in tube,Traumatic venipunctureBlood collected from area with hematomaVigorous shaking of tubes after collectionMilking the site when collecting capillary samples and blood collected using a small diameter needle.
18Test Collection Errors Timing of CollectionTimed DrawsTherapeutic Drug MonitoringPeak and trough collection timesBasal State CollectionsFasting requirements—no food or liquid except waterSpecimens affected by time of day, for example, cortisol
19Test Collection Errors Improper collection tube drawn for test orderedCollection tube not completely filledExample—light blue top tube for Coagulation Studies. Incomplete filling results in specimen dilution and erroneous Prothrombin and aPTT test results.
20Test Collection Errors Capillary Collections—finger stick or heel stickAppropriate siteHeel stick—sides of the bottom surface of the heelFinger stick—third or fourth fingers, perpendicular to fingerprint lines on fleshy pads on finger surfaceWarming—Warm before collection to increase capillary blood flow near skin surfaceCleaning—cleanse site with alcohol and allow to air dry
21Capillary Collections Massaging site to increase blood flowMilking site can cause hemolysis or tissue fluid contaminationFinger sticks—roll fingers toward fingertip at 1st finger joint several timesHeel sticks—gently squeeze infant’s heel before performing puncture.Perform puncture while firmly squeezing finger or heelWipe away first two drops of bloodEnsure that full blood drop wells up each time
22Capillary Collections Avoid touching capillary collection tube or micro collection tube to skin or scraping skin surfaceContaminates puncture siteBlood may become hemolyzedMixing micro collection tubes with additive frequently to avoid micro clotsCollecting tubes with additives firstProtecting tubes for bilirubin from light
23Blood Specimen Transport Errors Transport of blood specimens in the proper manner after collection ensures the quality of the sampleTimingSome specimens must be transported immediately after collection, for example Arterial Blood Gases.Specimens for serum or plasma chemistry testing should be centrifuged and separated within two hours
24Transport Errors Temperature Transport Container Specimens must be transported at the appropriate temperature for the required testOn ice—ABGs, AmmoniaWarmed degrees (37 C), cryoglobulinsAvoid temperature extremes if transported from via vehicle from other collection siteTransport ContainerSome samples need to be protected from light, for example, bilirubinTransport in leak-proof plastic bags in lockable rigid containers
25Error Prevention Phlebotomy Education Continuing Education Phlebotomists should have completed a standard academic course in phlebotomy and undergo thorough on-the-job training under the supervision of a senior phlebotomistContinuing EducationPhlebotomists should participate in regular educational competency assessments (written and observational)Professional LicensurePhlebotomy StaffingAdequate staffing to maintain collection standardsTechnologyUse of barcode scanners for patient identification
26Questions and Discussion How are pre-analytical errors prevented in your laboratory?What technology do you use to prevent human error?What systems does your hospital use to prevent errors by non-laboratory staff collecting blood?What pro-active improvements would reduce the number of pre-analytical errors?