Pre-analytical Laboratory Errors

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

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

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.

PhlebotomyErrors • 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

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

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

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

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

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

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

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

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

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

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

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

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

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.

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

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.

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

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

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

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

Transport Errors • Temperature • Specimens must be transported at the appropriate temperature for the required test • On ice—ABGs, Ammonia • Warmed --98.6 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

Error Prevention • Phlebotomy 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

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?

Pre-analytical Laboratory Errors