Point of care testing (POCT)

Point of care testing (POCT), Antidiuretic hormones ADH, Near patient testing, alternative site testing

1. POINT OF CARE TESTING (POCT) DR. OFONMBUK UMOH

2. OUTLINE Introduction Characteristics Classification of POCT Analytical principles Ethical considerations Recommendations Conclusion References 2

3. INTRODUCTION 3

4. 4 Modern advancements in semi-conductor engineering and nanotechnology incorporated into medical electronics has made it possible to adapt most of the analytical methods into devices that can be used at setting beyond the central laboratory. …introduction

5. POCT is appropriately defined as “any test that is performed outside the central laboratory , at a time which the test result enables a decision to be made, and actions taken promptly that can lead to an improved health outcome”. …definition 5

6. 6 Other names used to describe POCT includes: Bedside Off-site Satellite Kiosk Ancillary …testing. …introduction Near patient Physician office Extra-laboratory Decentralized Alternative site

7. In the hospital setting, POCT are commonly used in the emergency rooms, intensive care units, surgical recovery rooms and pediatric units for monitoring critical patients with acute and chronic conditions. However, POCT is now being incorporated into primary care, both to help in rapid diagnosis and promptness of triage to secondary care, as well as to manage chronic conditions in patients at stable state. …introduction 7

8. 8 Low instrument cost. One – or – two step operating protocol. First result in a minute or less. Portable instrument with replaceable consumable (cartridge or reagents). Simple operating procedures that do not require a laboratory – trained operator. Capable of performing direct specimen analysis on non-processed (whole blood or urine) samples. Characteristics of an ideal POCT analyzer

9. 9 Quantitative results with accuracy and precision comparable with those of the central laboratory. Built-in/integrated calibration and quality control. Ambient temperature storage for reagent – safe. Flexible test menus – toggle. Result stored & re-accessible, available for transmission, reproducible as hard copy.

10. 10 Central Laboratory POCT One site Multiple sites Limited instruments to perform bulk of analysis Multiple devices used Limited staff with focus on sample analysis Multiple staff with focus on patient care Staff with laboratory training and experience Staff with clinical training, not laboratory education Operational differences between POCT and Central Laboratory.

11. 11 Ketoacidosis causes inaccurate glucose results with POCT devices. Examine patients for ketoacidosis and screen urine for ketones first, before using Glucometer for them. POCT devices are not reliable at extremes of sample values when limit of detection are exceeded. LIMITATIONS OF POCT

12. 12 CLASSIFICATION OF POCT

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15. 15 Reflectance: in reflectance photometry, diffused light illuminates a reaction mixture in a carrier, and the reflected light is measured. Electrochemistry: this is concerned with the redox relationship between electrical potential, as a measurable and quantitative phenomenon. Fluorescence: the emission of light by a substance that has absorbed light or other electromagnetic radiation. ANALYTICAL PRINCIPLES OF POCT

16. 16 Immunoturbidimetry: is the process of measuring the loss of intensity of transmitted light due to the scattering effect of particles suspended in it. Electrical impedance: Based on Coulter principle. As fluid containing particles or cells is drawn through a micro-channel, each particle causes a brief change to the electrical resistance of the liquid. A counter detects these changes in electrical resistance and relates it to concentration.

17. 17 Spectrophotometry: which deals with the quantitative measurement of the transmission or absorbance properties of a colored mixture at specific wavelengths. Lateral flow/flow-through or solid phase immunoassay: antigens from the sample to be tested are attached to a surface. Then, a matching antibody is applied over the surface so it can bind the antigen. This antibody is linked to an enzyme, unbound antibodies are removed. detection antibody is added, forming a complex with the antigen.

18. 18 A-Conjugation (test) pad B-Sample (applicator) pad Lateral flow-through immunoassay strip

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20. 20 Convenience for both the attending physician/ nurse and patient. Reduced turnaround time for test results to expedite medical decision-making in operating rooms, emergency and intensive care units. Reduction in clinic visits, hospital admissions, and length of hospital stay due to faster services. ADVANTAGES OF POCT

21. 21 Better patient management due to improved visibility and interaction with a patient. Decreased manpower needs associated with test requesting and reporting, especially for patients necessitating tests several times a day. …advantages contd …

22. 22 Reduced risk of pre-analytical errors due to transporting specimen to core laboratory, processing, aliquoting …and communicating results back to clinical staff. Availability to a wider variety of sites e.g. rural areas, areas with limited infrastructure/personnel, and sites with underserved populations. …advantages contd …

23. 23 Little / no need for specimen processing. POCT is usually less traumatic for patients as smaller sample volume is required. Improved patient outcome. …advantages contd …

24. 24 POCT is significantly more expensive than the cost of central laboratory testing in the long run, due to the higher cost of disposable reagent for the POCT analyzers. Maintenance of quality control & quality assurance is difficult as anyone can run the analysis. Difficulties with documentation of test results, billing, and regulatory compliance. DISADVANTAGES

25. 25 Pre-analytical, analytical, and post-analytical issues are not easily recognized if tests are performed by untrained staff. Inter-individual variability in POCT results may be greater when compared with central laboratory testing. Managing reagent supply and storage at multiple sites is problematic. …disadvantages contd …

26. 26 POCT results are not always comparable due to differences in specimen types, technology, interfering substances, etc. Management of POCT is challenging—there are numerous operators to train, multiple sites to manage, and hundreds of POC tests to validate. …disadvantages contd …

27. 27 Equipment procurement and evaluation. Training and certification of operators. Quality control, quality assurance and audit. Maintenance and inventory control. Record keeping and documentation. ETHICAL & MANAGEMENT CONSIDERATIONS IN POCT

28. 28 There should be a POCT management committee established in the hospital. Pathologists should be in the POCT management team and responsible for validation and calibration of these devices. Recommendations

29. Disruptive innovation and advancement in analytical & fabrication technologies has radically seek to change the way which healthcare is delivered through the use of transportable, portable, and handheld instruments. POCT aim s to allow physicians and medical staff to accurately achieve real-time, lab-quality diagnostic results within minutes rather than hours to days. CONCLUSION 29

30. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics; fifth Ed., by Burtis et al. Martin A. Crook; Clinical Chemistry and Metabolic Medicine, 8th Edition. Clinical Chemistry; Principles, Techniques & Correlations, 7th Ed., by Bishop et al. Oxford Handbook of Clinical Pathology; 17th Edition, Oxford University Press, London. REFERENCES 30

31. THANK YOU 31