Introduction to the Principles of Laboratory Medicine

1. Introduction to the Principles of Laboratory Medicine

2. Module 1 What is laboratory medicine?

3. Case Scenario 1 • A 77-year old man presents to the emergency department with fevers and chills. He has had multiple urinary tract infections in the past and feels that this is “another one”. He has a history of diabetes mellitus, type 2 with diabetic nephropathy and chronic kidney disease. Physical exam is notable for an ill-appearing man with right flank tenderness. • How will the medical laboratory impact this patient’s care?

4. Case Scenario 1Discussion • Confirm clinical diagnosis • Urinalysis • Guide appropriate dosing of antibiotics • Dose adjustment for reduced GFR based on variables including serum creatinine • Guide selection of appropriate antibiotic therapy • With multiple course of treatment in the past there may be issues with antibiotic resistance Photo by Elizabeth Wantuch, MD

5. Call “the lab”…. • Today’s clinical laboratory is a complex arena offering an expansive menu of tests which continues to grow • Hundreds of millions of laboratory tests are performed every year in the United States

6. Influence of Laboratory Medicine on the quality and cost of healthcare • Lab tests consume about 2.3% of annual health care costs in the United States • It is noted in the literature that >70% of the objective data in a patient’s medical record comes from the clinical laboratory

7. WHAT is “Laboratory Medicine”? • Laboratory medicine (clinical pathology) is the medical discipline that specializes in the performance, reporting and interpretation of clinical laboratory tests in the provision of high quality patient care

8. WHO is “Laboratory Medicine” • Comprised of pathologists, doctoral-level laboratory scientists, technologists, and technicians • The laboratory medicine workforce has a vital role in the health care system managing and applying evidence-based, scientific testing techniques to support patient care

9. The specific types of clinical laboratories in health care institutions varies greatly from one place to another.

10. Listed below is a partial list of types of individual clinical laboratories • Blood Bank/Apheresis • Chemistry/Immunoassay • Hematology and Coagulation • Urinalysis, Fluid Analysis and Medical Microscopy • Cytogenetics • Endocrinology • Immunoserology • Microbiology (including Bacteriology, Virology, Parasitology, etc.) • Molecular Pathology • Tissue Typing/HLA • Toxicology

11. Each lab may have one medical director and one technical specialist responsible for testing services and quality of the lab • Some labs require a combined leadership group of 2-3 directors and multiple technical specialists

12. Additional Terms Photo by Theresa Kristopaitis, MD

13. “Reference lab” • In our medical center the lab tests performed at reference labs are often called “send out labs” • Clinical reference laboratories provide testing services for patients and healthcare providers • The labs performed are generally specialized tests that are infrequently ordered or that require specialized equipment

14. “Point of Care Testing” Photo by Theresa Kristopaitis, MD Point of Care Testing (POCT) is laboratory testing performed on simpler devices at the point of care (e.g., the bedside) and often by non-laboratory personnel

15. Case Scenario 2 • A 5-year old boy is at his physician’s office with fever, sore throat and severe pain with swallowingx 2 days. On physical exam his temperature is 390C. There is tonsillarerythema and swelling with white exudates. • What point of care test do you think was performed? • A rapid Streptococcal antigen test • The test is positive. How does this impact the care of the patient? • Appropriate antibiotics are prescribed • What if the test were negative? • The physician understands the sensitivity and predictive value of the rapid antigen test. If the clinical suspicion for Streptococcal pharyngitis is high a throat culture would be submitted

16. Case Scenario 3 • A 5-year old boy is at his physician’s office with low grade fevers, sore throat, runny nose, watery eyes for the past week. On physical exam he is afebrile. There is minimal tonsillar swelling and erythemawithout exudates. The boy’s parents insist that he be treated with antibiotics. • The physician has a low clinical suspicion for Streptococcal pharyngitis but does perform a POCT Strep antigen screen. The result is negative. How does this impact patient care? • Support to not provide unnecessary antibiotic therapy for what is likely a viral upper respiratory tract infection

17. What is the Point of “POCT”? • The key objective of POCT is to produce a result more quickly • Therefore the utility of POCT is in the immediacy of responseand effect on medical decision making • Due to advances in technology, clinical needs and a number of other factors, POCT may be the most rapidly growing segment of laboratory testing worldwide

18. What POCT is available for the following patients? • 24-year old woman with amenorrhea x 2 months? • Urine HCG • 42-year old man with diabetes mellitus? • Glucose, HgbA1c, urine microalbumin • 63-year old woman with atrial fibrillation on warfarin • INR • 78-year old man presenting to the ED with 10/10 crushing chest pain • Troponin

19. Proceed to “Module 2: The Diagnostic Testing Process”