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Pre-analytical Laboratory Errors

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Presentation on theme: "Pre-analytical Laboratory Errors"— Presentation transcript:

1 Pre-analytical Laboratory Errors
Tim Guirl MT (ASCP) Phlebotomy Instructor North Seattle Community College Health & Human Services Division

2 Objectives Identify the significant pre-analytical errors that can occur during blood specimen collection and transport Explain the various means of pre-analytical error prevention List proactive steps to reduce potential pre-analytical errors associated with blood collection and transport

3 Introduction Three phases of laboratory testing: pre-analytical, analytical and post-analytical Pre-analytical—specimen collection, transport and processing Analytical—testing Post-analytical—testing results transmission, interpretation, follow-up, retesting.

4 Phlebotomy Errors Phlebotomy is a highly complex skill requiring expert knowledge, dexterity and critical judgment It 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

5 Pre-analytical errors
Pre- and post-analytical errors are estimated to constitute 90% of errors Errors at any stage of the collection, testing and reporting process can potentially lead to a serious patient misdiagnosis Errors during the collection process are not inevitable and can be prevented with a diligent application of quality control, continuing education and effective collection systems

6 Types of Collection Errors
Patient Identification Phlebotomy Technique Test Collection Procedures Specimen Transport Specimen Processing

7 Patient Identification Errors
Errors in correctly identifying the patient are indefensible Reasons for patient identification errors Proper positive patient identification procedures not followed Patient 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

8 Patient Identification Errors
Specimen tubes unlabeled Requisition or collection tube labels not affixed to tubes Requisition or collection tube labels in bag containing collection tubes Requisition or collection tube labels rubber-banded to tubes Collection tube labels not affixed to all tubes Specimen collection tubes labeled insufficiently with at minimum patient’s full name, date/time of collection, phlebotomist’s initials

9 Patient Identification Errors
Collection tubes labeled with the wrong patient Wrong computerized labels affixed to collection tubes at bedside Collection tubes not labeled at the time of collection Collection tubes incorrectly labeled by someone other than the phlebotomist who collects the specimen

10 Patient Complications
Some patient variables that affect blood specimens Diet Fasting Exercise Obesity Allergies to alcohol or iodine used to clean venipuncture site Use alternative cleanser such as chlorhexidine

11 Phlebotomy Technique Errors
Phlebotomy technique is important Ensures test result validity Minimizes trauma to patient Minimizes potential for phlebotomist injury Reduces recollections Vein selection essential for successful venipuncture Three veins in antecubital fossa in order of selection (1) median cubital (2) cephalic (3) basilic

12 Phlebotomy Technique Errors
Site Selection Avoid sites with IV Use alternative arm or draw below IV to avoid contamination/dilution from IV Document arm if IV Mastectomy—avoid site due to lymphostasis Infection risk/alteration in body fluids and blood analytes Edematous areas —avoid due to accumulation of body fluids Possible contamination/dilution of specimen

13 Phlebotomy Technique Errors
Venous Access Difficulties Obstructed, hardened, scarred veins Veins difficult to locate Use of Alternative sites Top of hand/Side of wrist Areas to avoid Vein Collapse Use of appropriate needle size Smaller evacuated collection tube

14 Phlebotomy Technique Errors
Tourniquet Application Tourniquet tied too close to the venipuncture site can cause hematoma Veins 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 results Tourniquet should be released as soon as needle is in the lumen of the vein and blood flow established

15 Phlebotomy Technique Errors
Cleansing of venipuncture site Thorough cleaning with alcohol Allow alcohol to dry completely to avoid stinging sensation upon needle entry and hemolysis of sample Samples such as blood cultures should be collected using iodine to cleanse site to ensure sterility of sample Recollection rate for blood cultures ranges due to contamination is as high as 50% in hospitals with increased costs, patient overtreatment

16 Phlebotomy Technique Errors
Correct collection system Evacuated tube system (Vacutainer) for large veins in antecubital fossa Syringe for small, fragile veins or veins outside antecubital fossa Venous access Needle entry should be at 15 to 30 degrees depending on depth of vein Needle entry should be in same direction as vein, centered over vein Anchor vein to prevent movement during needle entry and to reduce pain to patient

17 Test Collection Errors
Order of Draw Order 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 tube Hemolysis Blood collected insufficient to amount of additive in tube, Traumatic venipuncture Blood collected from area with hematoma Vigorous shaking of tubes after collection Milking the site when collecting capillary samples and blood collected using a small diameter needle.

18 Test Collection Errors
Timing of Collection Timed Draws Therapeutic Drug Monitoring Peak and trough collection times Basal State Collections Fasting requirements—no food or liquid except water Specimens affected by time of day, for example, cortisol

19 Test Collection Errors
Improper collection tube drawn for test ordered Collection tube not completely filled Example—light blue top tube for Coagulation Studies. Incomplete filling results in specimen dilution and erroneous Prothrombin and aPTT test results.

20 Test Collection Errors
Capillary Collections—finger stick or heel stick Appropriate site Heel stick—sides of the bottom surface of the heel Finger stick—third or fourth fingers, perpendicular to fingerprint lines on fleshy pads on finger surface Warming—Warm before collection to increase capillary blood flow near skin surface Cleaning—cleanse site with alcohol and allow to air dry

21 Capillary Collections
Massaging site to increase blood flow Milking site can cause hemolysis or tissue fluid contamination Finger sticks—roll fingers toward fingertip at 1st finger joint several times Heel sticks—gently squeeze infant’s heel before performing puncture. Perform puncture while firmly squeezing finger or heel Wipe away first two drops of blood Ensure that full blood drop wells up each time

22 Capillary Collections
Avoid touching capillary collection tube or micro collection tube to skin or scraping skin surface Contaminates puncture site Blood may become hemolyzed Mixing micro collection tubes with additive frequently to avoid micro clots Collecting tubes with additives first Protecting tubes for bilirubin from light

23 Blood Specimen Transport Errors
Transport of blood specimens in the proper manner after collection ensures the quality of the sample Timing Some 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

24 Transport Errors Temperature Transport Container
Specimens must be transported at the appropriate temperature for the required test On ice—ABGs, Ammonia Warmed degrees (37 C), cryoglobulins Avoid temperature extremes if transported from via vehicle from other collection site Transport Container Some samples need to be protected from light, for example, bilirubin Transport in leak-proof plastic bags in lockable rigid containers

25 Error 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 phlebotomist Continuing Education Phlebotomists should participate in regular educational competency assessments (written and observational) Professional Licensure Phlebotomy Staffing Adequate staffing to maintain collection standards Technology Use of barcode scanners for patient identification

26 Questions 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?

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