Pre - analytical Variables in Clinical Chemistry

1. Pre-analytical Variables in Clinical Chemistry Aparna Jha Ahuja MD, MBBS, PG Hospital Management, IFCAP Head, Medical Affairs East Europe/Middle East/Africa BD Diagnostics—Preanalytical Systems aparna_ahuja@europe.bd.com; aparnahuja@yahoo.co.in

2. The total testing cycle: “Brain to brain” Patient preparation Test ordering Specimen acquisition Specimen transport and processing Result reporting Specimen analysis

3. Pre-Analytical, Analytical, Post-Analytical • Errors in any phase can lead to problems • Erroneous results • Inappropriate patient treatment and associated costs • Inconvenience to patients due to call backs and additional draws • Wasted consumables, investigation costs, etc. • Negative impact on patient care

4. Pre-analytical errorsNeed for increased understanding • Through quality initiatives, error rates have dropped • Pre-analytical errors estimated to be 4 to 5 times greater than observed in other phases; ~70% • Most are a consequence of poor specimen quality

5. Most laboratory testing errors occur before sample is placed on the analyzer Perceived need for test Test request requisition Patient preparation Specimen acquisition Specimen transport Specimen processing Improvement Opportunity! 32-75% Pre-analytical Phase Analytical phase 4-32% Specimen analysis • Report generation • Report retrieval • Report interpretation Post-analytical Phase 9-55% Howanitz and Howanitz, Clin. Lab. Med, 3:541-551, 1983; Bonini et al., Clinical Chemistry 48:5, 691-698, 2002

6. Specimen Workflow Transport Sample to Lab Section Transport Sample to Lab Receive Sample in Lab Prepare Sample for Testing Collect Sample Order Test • Locate patient • Prep patient • Draw sample • Bedside • Home • Doctor’s office • Draw station • Label • Dispose of supplies • Prioritize sample for transport • Send sample to lab • Pneumatic tube • Robot • Hand carry • Courier • Accession • Apply/verify sample label • Bar code for testing • Identify STAT tests • Rack sample • Send sample to appropriate lab section • Main lab • Reference lab • Re-rack • Centrifuge • Aliquot • Pre-treat • Re-rack • Select test • Complete order form • Receive test order • Deploy staff for collection • Note urgency level • Collect supplies Inventory Management

7. Specimen Management Process: Causes of Errors Analytic Processing Pre-Analytic Processing Storage Disposal Collection Transport • Wrong person • Wrong container • Wrong time • Wrong order • Missing pre-draw instructions • Illegible collection data on label • Collection data omitted • Interfering substances • Lost containers • Broken containers • Bar code labels misaligned • Loose labels • Inability to locate stored samples • Inability to track samples • Missing Label • No bar code labeling • Wrong bar code applied in the lab

8. Factors contributing to the increase in pre-analytical errors Decreased # of Med Techs to collect & supervise Present Past Specimens collected in and out of hospital All specimens collected in hospital Frequent staff turnover; training issues Collected by medical technologists # of instruments & methods increasing Specimens carried to laboratory Analytes monitored over time Test menu exploding Limited # of test menus & instruments ‘Routine’ test sensitivity increasing Test analytes at 10-3 Impact on managing preanalytical variables: specimen collection, handling, processing & transport Low sample volumes required Large test sample Results Obtained Results Obtained

9. Pre-analytical factors Fixed Variable Technical Within control of phlebotomist/laboratory staff • Biological • Beyond control of phlebotomist/laboratory staff

10. Fixed Fixed pre-analytical factors Gender Race Age Pregnancy Diet Exercise Environment/Lifestyle

11. Variable Variable pre-analytical factors • Patient Identification • Collection Related • Collection Time • Collection Site • Phlebotomy Technique • Sample ID • Sample Handling • Mixing • Centrifugation • Sample Transport and Storage

12. Specimen identification and labeling • Positive patient ID prior to specimen collection; at least 2 patient identifiers • Use active—not passive communication • Query system • Mechanical means • Information technology-based patient safety specimen management systems

13. Labeling errors

14. Identification errors in clinical laboratories range from 0.1% to 5.0% • Rate of patient identification errors: 379 errors/1 million tests • 85% of errors detected before results released • 345 adverse events reported; >70% resulted in significant patient inconvenience with no known change in treatment or outcome • Extrapolating to all US hospital-based labs: >160,000 adverse events/year result from misidentification of patients’lab specimens 2006 Q-Probes study of 120 institutions Valenstein et al, Arch Pathol Lab Med 130:1106-13, 2006

15. Practices that reduce specimen identification errors • Ongoing monitoring of identification errors • Ensuring new patients are properly identified • Using multiple identifiers to ensure accurate investigation in laboratory medicine • Matching requisitions to test ordered in the computer Valenstein et al, Arch Pathol Lab Med 130:1106-13, 2006

16. Specimen labeling issues 147 participating laboratories identified a rate of labeling errors of 0.92 per 1000 labels • Best labs (90th percentile) 0.22 errors / 1000 labels • Worst labs (10th percentile) 52.27 errors / 1000 labels Two variables found to be statistically associated with lower specimen labeling error rates • Current, ongoing quality monitors for specimen ID • 24/7 phlebotomy services for inpatients Wagar, E.A. et al. Arch Pathol Lab Med 132:1617-22, 2008.

17. Label misalignment can cause increased cost • Large analytical problems; instrument barcode readers cannot read the barcode • A deviation of only 8% from vertical axis is enough to cause a problem • Tubes need to be relabeled in the lab • Potential to create a patient ID error • Adds unnecessary cost to testing process

18. Storage of Collection Devices Environmental conditions Expiration dates Technical Factors Needle & syringe vs. evacuated system Order of draw Type of additive Filling of tube Mixing of tube; number of inversions Processing Time Centrifugation Temperature Storage Impact of collection and processing practices

19. Change in total protein concentration ( ) and lactate dehydrogenase activity ( ) in serum during a 15 min tourniquet application time

20. Specimen quality:syringe vs. evacuated tube

21. Insufficient quantity • ~ 11% of rejected specimens • Altered blood : additive ratio • May have dilution effects with liquid additive • Short sampling on instrument

22. Specimen mixing Why Consequences if not mixed Tubes with anticoagulants will clot SST tubes will not clot completely Specimen will often need to be recollected • Most tubes contain an additive or clot activator that needs to be mixed with the blood sample • Tubes with anticoagulantssuch as EDTA need to be mixed to ensure the specimen does not clot

23. Incomplete Clotting • Presence of fibrin • Instrument downtime due to probe clogging • Reduced sample volume • Re-spinning • Cell lysis • Mixing of 2 serum populations

24. Transport related causes • Transport • Pneumatic tube • Courier • Shipment • Temperature and humidity • Time • Specimen integrity • Exposure to light

25. Temperature and time effect of storage of clotted blood without anticoagulant on various serum analytes

26. Reasons for rejecting Chemistry Specimens

27. Specimen hemolysis • Common preanalytical error • Phlebotomy decentralization • Doubles hemolysis rates • Increases specimen rejection rates and re-draws • Highest incidences in ED and Labor & Delivery • Interferences • Release of intracellular components (K+, LD) • Colorimetric measurements • Interferes with clotting • Optical methods • Mechanical Methods

28. Hemolysis causes In vivo In vitro Catheter IV collection Drawn from hematoma Capillary collection Phlebotomy equipment Phlebotomy antiseptic Tourniquet time Location of stick Vigorous mixing In tube Traumatic draw Tube under filling Syringe transfer • Hemolytic transfusion Rx, autoimmune warm Ab • Hereditary spherocytosis, G6PD deficiency, sickle cell anemia, • Paroxysmal nocturnal hemoglobinuria, DIC, Burns, Liver & Renal Disease, • Anti-malarials, aspirin, chloramphenicol • Malaria, Clostridia, • March hemoglobinuria, prosthetic heart valves

29. Hemolysis survey European Preanalytical Scientific Committee (EPSC), in collaboration with International Federation of Clinical Chemistry (IFCC) Working Group on Patient Safety, designed a questionnaire to collect data on prevalence and management of hemolytic specimens referred to clinical lab for clinical chemistry testing 391 lab respondents • 9%: were not aware that some lab tests might be affected by hemolysis • 42%: did not systematically monitor number and origin (e.g., wards, facilities) of hemolyzed specimens that they receive in their lab

30. CAP Hemolysis Study

31. Hemolysis scales used (710 labs) Instrument scale only 11% Visual scale only 48% Both visual & instrument scale 41%

32. Hemolysis rejection practices No specimens rejected for any hemolysis4% All specimens rejected for any hemolysis8% Some specimens rejected based on hemolysis level 88%

33. 21/69 most commonly used hemolysis descriptive terms

34. Use of 20 cutoff hemolysis terms

35. Analyte specific hemolysis policies

36. Changes in various analytes with increasing haemolysis in a dual wavelength routine analyzer

37. Interference of haemoglobin with various diazo methods to measure bilirubin

38. Preanalytical errors impact patient safety Impact on Patient Impact on Healthcare Facility PreanalyticalErrors • Hemolysis • Under-filled blood collection tubes • Clotted blood samples/improper mixing • Sample collected from wrong patient • Samples labeled incorrectly • Mis diagnosis • Inappropriate treatment/therapy • Inappropriate blood transfusion—can be fatal • Additional pain & discomfort due to multiple blood collection • Delay in appropriate treatment/therapy • Prolonged or unnecessary hospital stays due to inappropriate treatment • Increased staff costs for investigations & additional lab testing • Cost of possible legal action due to serious or fatal medical errors • Increased staff time for maintenance of costly lab equipment & increased downtime of lab analyzers due to clots • Increased cost of staff time & equipment for redrawing samples

39. Preanalytical Variables Have to Be Managed • The laboratory must monitor and evaluate the overall quality of the preanalytic systems and correct identified problems. • The laboratory must establish and follow written policies and procedures for an ongoing mechanism to monitor, assess, and when indicated, correct problems identified in the preanalytic systems. • The preanalytic systems assessment must include a review of the effectiveness of corrective actions taken to resolve problems, revision of policies and procedures necessary to prevent recurrence of problems, and discussion of preanalytic systems assessment reviews with appropriate staff. • The laboratory must document all preanalytic systems assessment activities.

40. Quality results are dependent on quality pre-analytics; results are only as good as the weakest link

41. Pre-analytical variables must be managed Your patients are counting on it