Point-of-Care Testing: What does is really mean today and is it relevant to the local situation ?

1. Point-of-Care Testing: What does is really mean today and is it relevant to the local situation ? Patrick St.Louis Département de biochimie Hôpital Ste-Justine et Université de Montréal Montréal, Canada SCPC, Havane, 2004

2. Point-of-Care Testing (POCT)  the analysis of (biochemical) parameters at or near the patient’s bedside. A new name for satellite lab testing ? ER, OR, ICU Clinical benefit of POCTreduces the time interval between the decision to order the test and the clinical action based on the test result (total turn-around time; TAT) test needed/request specimen  lab test/result report

3. One classification of POCT • in vitro (traditional)  manual: urinalysis, occult blood  instrumented: glucose meters, ACT, gases • in vivo  invasive e.g. pulmonary artery catheter  non-invasive e.g. transcutaneous bilirubin, pulse oximetry (transcutaneous) • ex vivo  in-line sensors; through an extracorporeal circuit

4. some examples

9. The present scope of POCT: Tests possible in the ER • Blood gases, electrolytes, creatinine, lactate • hemglobin/hematocrit • cardiac markers: myoglobin, troponin, BNP - NPV for Dx of CHF = 98%; precludes the need for echocardiography • Coagulation: PT/INR, ACT, D-dimer • glucose • urinalysis, urine pregnancy test • hemoccult/gastroccult/pH • drugs screens • rapid HIV

10. How is POCT used and what are its advantages? 1. POCT for glucose: • improves response time for  high risk neonates with hypoglycemia,  diabetics in hyperglycemia  patients in Tight Glycemic Control protocols • decreases iatrogenic blood loss - l of capillary blood

11. 2. Clinical applications of anticoagulation therapy • OR - cardiac surgery, interventional cardiology and radiology (heparin) • critical care • satellite sites: dialysis, ECMO, anticoagulation clinic • Patients on coumadin/warfarin therapy

12. Monitoring anticoagulation therapy treamentmonitor with • heparin (intrinsic pathway) ACT, aPTT • coumadin/warfarin PT/INR (extrinsic pathway) • direct thrombin inhibitors ??? (common pathway) • Thrombolytics (clot) TT, fibrinogen

13. POC coagulation testing for monitoring patient status post-thoracic/cardiovascular surgery; studies have shown that this permits the evaluation and management of microvascular bleeding:  complications - blood loss - need for blood and blood products - re-operations (repeat surgery)  overall cost of care  satisfaction

14. Patients on coumadin/warfarin therapy: • Monitor using PT/INR testing • Patient self-testing a major direction with clear advantages

15. There are Advantages and Problems related to the use of instrumented POCT: POSITIVES  for the most part these POCT devices are robust and easy to use; require minimal maintenance  testing process is generally simple  results are usually reliable

16. Data management in instrumented POCT systems • calibration curves, AMR • QC: lot information, automated QC • material information: strip lot numbers, parameters • identifiers: operator, patient • results: tests, QC, unique event time stamp • lock-out: operator and patient ID, QC demanded, prohibits use of expired reagents • have comment codes, response protocols • notices and messages

17. Issues with POCT devices • method characteristics : AMR (measuring range), linearity, precision  usually not as good as central lab • sample type in relation to normal (reference) intervals-blood glucose: capillary/venous blood plasma/whole blood • QC; operator attitude to QC • results and charting; ensuring that the information gets to the Laboratory Information System and into the patient chart - Connectivity

18. POSSIBLE CAUSES OF POOR PERFORMANCE • novel technologies • transcutaneous bilirubin: interferences, calibration • hematocrit determination by conductivity • interferences • gel separator tubes • drugs in patient samples • Extraneal (icodextrin; a dialysis solution)- GDH-PQQ-based glucose meters • patient-related • high hematocrit in neonatal samples for glucose

21. THE COST FACTOR

22. No standardised manner of calculating costs for POCT Generally the cost/patient result is higher than the corresponding central laboratory cost Some factors: • reagent costs: the single-use disposable strip or cassette or multi-test packs versus standard laboratory reagent packaging in hundreds of tests; the incremental effects of utilisation on costs  more costs less • equipment costs: additional to central lab system • labour costs: operators, coordinators, • other: QC, training, re-certification, regulatory requirements

23. Cost can also be affected by the total number of tests; demand for confirmation, correlations. 1. POCT for glucose; central laboratory volume (6 months): pre-POCT = 20406; post-POCT = 24028; figures were not related to bed occupancy or to patient mix; do not include glucose meter (POC) testing (Lum, 1997) Similar results from a recent study at HSC, Toronto 2. HSJ Glucometer program projected annual workload: 40,000 actual year 2000: patients = 35,459 controls = 22,931 actual total 58,390

24. QC and QA in POCT

25. Quality Control POCT, like all laboratory testing, demands regular QC testing to assure acceptable performance (CAP Q-probes)  For single-use reagent test strips or cassettes - lot validation  Instrumented, multitest systems - traditional QC procedures • Electronic QC: these are simulators designed to monitor the performance of the hardware/reader part of the system; they do not evaluate the chemistry/reagent part of the system. • iQM: used in the IL GEM 3000; FDA approved; a complex algorithm using the same liquid material for QC and calibration

26. Just as in traditional central laboratory testing, QA is important in POCT; there are however some different issues With POCT • variable number of individual devices; multiple sites; • many operators; training? • need clear protocols • ensure appropriate QC practices; resistance to QC • assure proper storage of reagents, supplies • eliminate use of expired reagents, cassettes, slides, etc • verify error-free operator and patient ID • results: documentation and reporting

29. HOW CAN YOU OPTIMALLY USE POCT? • manual tests are already used • Common instrumented POCT types  glucose meters blood gas analysers (electrolytes, creatinine, lactate) coagulation analysers cardiac marker systems urinalysis instruments

30. glucose meters • personal or hospital type; relative complexity and costs of instruments • lack of QC and data handling capacity in P types • reliability of results for close clinical management; American Diabetic Association and NCCLS guidelines  neither should be used for diagnosis. • cost of strips; cost of QC material; • Validation of instrument performance; NCCLS guidelines for POCT performed outside lab support

31. Blood gases; single use i-STAT and IRMA • multi cassette ABL700 series • GEM Premier series; more tests; reliable, less costly on a per/test basis; wastage; how portable? • co-oximetry: O2 sats, Hb and Hct assays, technology

32. Trends in POCT

33. MUCH OF POCT IS NO LONGER ACUTE The introduction of new clinical standards is motivating physicians to demand testing be done closer to the patient. (Dr. R. Christenson, U. of Maryland) Out-patient and specialty clinics EVIDENCE BASED LABORATORYMEDICINE NACB/AACC project for POCT  impact on patient outcomes; looking at all areas - gases, electrolytes, glucose, creatinine, coagulation, fertility, peri-natal testing (fetal scalp pH, fern testing, pH testing for ruptured membranes), transcutaneous bilirubin, cardiac markers, etc

34. CONCLUSIONS Like the “Core Lab” concept, POCT is here to stay ? Is it more cost-effective? ? Better patient care ? more satisfaction: patient and caregiver Newer paradigms ? is POCT now physician driven; is this any different from the past? Trends in evidence-based POCT