檢驗結果異常的原因分析與臨床因應

1. 檢驗結果異常的原因分析與臨床因應 謝文祥

2. 2013 HospitalNational Patient SafetyGoals • Identify patient correctly • Improve staff communication • Use medicines safely • Prevent infection • Check patient medicines • Identify patient safety risks • Prevent mistakes in surgery The Joint Commission Accreditation Hospital

3. 2013LaboratoryNational Patient Safety Goals • Identify patient correctly • Improve staff communication • Prevent infection The Joint Commission Accreditation Laboratory

4. 年度目標的演進 Taiwan Joint Commission on Hospital Accreditation

5. 2008-2009年度目標的演進 1.提升用藥安全 2.落實醫療機構感染控制 3.提升手術安全 4.預防病人跌倒及降低傷害程度 5.鼓勵異常事件通報及資料正確性 6.提升醫療照護人員間溝通的有效性 7.鼓勵病人及其家屬參與病人安全工作 8.提升管路安全 Taiwan Joint Commission on Hospital Accreditation

6. 2010-2011年度目標的演進 提升用藥安全 落實醫療機構感染控制 提升手術安全 預防病人跌倒及降低傷害程度 鼓勵異常事件通報及資料正確性 提升醫療照護人員間溝通的有效性 鼓勵病人及其家屬參與病人安全工作 提升管路安全 加強醫院火災預防與應變 Taiwan Joint Commission on Hospital Accreditation

7. 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.

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

9. Phlebotomy Errors • Phlebotomy is a highly complex skill requiring expert knowledge, dexterity, and critical judgment • It is estimated that one billion vein-punctures are performed annually in the U.S. • Phlebotomy Errors may cause harm to patients or result in needle-stick injury to the Phlebotomist

10. Pre-analytical errors • Pre- and post-analytical errors are estimated to constitute 90% of errors • Errors at any stages 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

11. Types of collection errors • Patient Identification • Phlebotomy Technique • Test Collection Procedures • Specimen Transport • Specimen Processing

12. 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 patient to state or spell their full name (inpatients / outpatients ) • Patient identification by staff or family member if patient unable to identify him/herself

13. 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

14. 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

15. Patient Complications • Some patient variables that affect blood specimens • Diet • Fasting • Exercise • Obesity • Allergies to alcohol or iodine used to clean vein-puncture site • Use alternative cleanser such as chlorhexidin

16. 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 Vein- puncture • Three veins in antecubital fossa in order of selection (1) median cubital (2) cephalic (3) basilic

17. 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

18. 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

19. 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

20. 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

21. 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

22. 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

23. Test Collection Errors • Timing off 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

24. 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

25. 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

26. 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

27. 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

28. Good Sample Handling • Draw the correct volume • Mix : It’s essential • Allow time to clot • Spin under the correct conditions • Aspirate, Don’t pour • Refer to the product insert or package labeling supplied by the manufacture of any blood collection product for complete recommendations on sample collection and processing • Reference : CLSI(H3-A6)2008 / CLSI(H18-A3)2004

29. 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

30. 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

31. 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

32. 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?

33. 檢體採集作業流程 • 病人同意：醫療或研究需求？ • 病人辨識：原則、方法(時機、頻率) • 病人保護：隱私 、安全(消毒、暈針) • 衛教說明：口頭、單張、媒體、手冊 • 正確採集：檢體量、檢體種類 • 保存傳送：保存劑(抗凝劑) 、溫度、包裝 • 檢體訂定允收原則的必要與省思？ • 檢體重採的限制與省思？ Taiwan Hospital Association 2007

34. 檢驗前流程(程序) Pre-examination Procedure (Process)

35. Efficiency and Effectiveness (about Quality and Utility) • Sampling Identification • Barcode labeling • Single tube (Close Container System) • Inside Aliquot (Auto-Centrifugation) • TLA (Auto-Transportation)

36. 案例一 • 病人晚上掛急診， 白血球(WBC)報告為630，第二天上午主治醫師請CCU再追蹤一次WBC，病人的報告為17530，因兩次報告差異大，所以CCU專科護理師打電話至檢驗科，請醫檢師重驗前一天於急診所驗的WBC，但醫檢師表示因當時所抽的血量不夠，無法再重驗，所以也無法確認前一天急診WBC報告是否正確?

37. 抽錯病人 • 編號錯誤(貼錯標籤) • 血液稀釋 • 血液凝固 • 用錯試管(抗凝劑錯) • 操作錯誤/儀器故障(吸取不足) • 儀器故障/試劑變質 • 報告填錯

38. 案例二 • 病人因頭部鈍傷，頭暈至急診就醫，醫師診視後，給予打上點滴，抽CBC、生化檢驗，隨後醫檢師通報危險值，告知醫師血紅素3.8 ，詢問病人表示平時無貧血症狀且還有在捐血，故依照醫矚再抽第二次CBC ，血紅素:13.3?

39. 抽錯病人 • 編號錯誤(貼錯標籤) • 血液稀釋 • 血液凝固 • 用錯試管(抗凝劑錯) • 操作錯誤/儀器故障(吸取不足) • 儀器故障/試劑變質 • 報告填錯

40. 檢驗流程(程序) Examination Procedure (Process)

41. Efficiency and Effectiveness (about Quality and Utility) • Calibration • Internal Quality Assessment (QC) • External Quality Assessment (PT)

42. 案例三 • 於03：53 抽血aPTT data 180.4 sec，當時血液室電話告知通報危險值，護理人員立即告知主治醫師及住院醫師，主治醫師立即囑輸注FFP 2U IVD st、vit K1 1amp IVD st，並請住院醫師追蹤aPTT prolong原因，住院醫師詳細評估後，囑recheck aPTT、PT data，表示第二次追蹤若真的是有延長情形，預備檢驗其他凝血功能。於05：39再驗結果 aPTT 34.7sec、PT 14.4sec（抽血時尚未執行FFP及K1醫囑），電話詢問血液室人員為何兩次檢驗數值差距大?檢驗室人員才表示第一次檢驗數值是因為機台故障（未主動告知SICU），故第二次檢驗數值才以人工計數執行。[如何發現機台故障，補救程序為何?]

43. 抽錯病人 • 編號錯誤(貼錯標籤) • 血液稀釋 • 血液凝固 • 用錯試管(抗凝劑錯) • 操作錯誤/儀器故障(吸取不足) • 儀器故障/試劑變質 • 報告填錯

44. 案例四 • 病人3/28由ER入,因H/D3/30轉床,病人CPK、CK-MB、Troponin-I一直偏高所以Q6h追蹤。3/31 6:28 Na:129、K:3.2、BUN:35、Cr:1.1、CPK:36,CK-MB:6、Troponin-I:0.04，早上7點向值班醫師報data時，值班醫師覺得報告值差異太大， 囑咐護理人員再抽血重驗一次CPK、CK-MB、Troponin-I，data為CPK:12364、CK-MB:268、Troponin-I:＞30， 9點多檢驗科人員來電表示，檢驗科夜班人員可能做錯檢體，故要再重新做一次(用早上6點多的檢體)，10:17檢驗人員再補發早上6:28報告為Na:142、K:3.9、BUN:21、Cre:3.1、CPK:12136、CK-MB:268、Troponin-I:＞30，已告知值班醫師及單位主管。[另一檢體也是錯誤，是否有處理？]

45. 抽錯病人 • 編號錯誤(貼錯標籤) • 血液稀釋 • 血液凝固 • 用錯試管(抗凝劑錯) • 操作錯誤(拿錯檢體)/儀器故障(吸取不足) • 儀器故障/試劑變質 • 報告填錯

46. 檢驗後流程(程序) Post-examination Procedure (Process)

47. Efficiency and Effectiveness (about Quality and Utility) • Systematical Review of Results • Auto-Storage of Samples • Auto-Validation of Results • HRRR (Critical / Alert Reports)

48. 案例五 • 病人有滴注抗凝劑之藥物，醫囑開立需依計算aPTT之倍數來微調滴數，跨班人員發現檢驗數值與前班之數據差距相當大而發現前一班計算結果錯誤。[為何要算?]

49. 抽錯病人 • 編號錯誤(貼錯標籤) • 血液稀釋 • 血液凝固 • 用錯試管(抗凝劑錯) • 操作錯誤(拿錯檢體)/儀器故障(吸取不足) • 儀器故障/試劑變質 • 報告填錯(計算錯誤)

50. 案例六 • 因creatin data :7.0，醫師懷疑因藥物引起的急性腎衰竭，預安排腹部超音波及會診腎臟內科，並停止抗生素的使用，但患者U/O:3.15ml/kg/hr，小便淡黃清澈，為慎重起見，醫囑再次抽血BUN/Cr，檢體送出後，檢驗科人員電話告知，Cr data 錯誤，正確值為0.7，值班醫師知情後，緊急停止所有相關檢查。[是否用新檢體?]