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Laboratory errors in medical practice

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Laboratory errors in medical practice

  1. 1. Laboratory Errors inMedical PracticeMohammad Tanvir IslamAssistant Professor , MedicineBangabandhu Sheikh Mujib Medical University
  2. 2. “Anyone who has never made a mistake has never tried anything new.”
  3. 3. “Smart people learn from their mistakes. But the real sharp ones learn from the mistakes of others.” Brandon Mull
  4. 4. Why did the TITANIC sink?
  5. 5. Laboratory Testing Cycle Pre-Analytic phase Ordering a test Order transferred to lab Identifying information entered Specimen obtained Post analytic phaseReport generatedResult conveyed to clinician Analytic phaseData interpreted Specimen analyzedClinical response to result
  6. 6. • 0.10- 3.0%• Mostly pre-analytic and post-analytic• Analytic mistakes are <10% of all errors
  7. 7. Pre-Analytic• Inappropriate test request 46%-68.2%• Order entry errors• Misidentification of patient• Container inappropriate• Sample collection and transport inadequate• Inadequate sample/anticoagulant volume ratio• Insufficient sample volume• Sorting and routing errors• Labeling errors
  8. 8. Questions to ask Before ordering a Test• Why is the test being ordered• What are the consequences of not ordering the test• How good is the test in discriminating between Health versus Disease• How are the test results interpreted• How test results influence Mx & outcome
  9. 9. Clinical Performance Characteristics• Prevalence• Sensitivity• Specificity• Efficiency• Positive Predictive Value• Negative Predictive Value
  10. 10. • In useful test sensitivity+specificity should be>170• Prevalence of a disease can affect the PPV /NPV• Cutoff value of a test can change the sensitivity & specificity
  11. 11. Shotgun versus Rifle
  12. 12. Common Causes of Pre-analytical ErrorBiological• Age Diseases:• Sex • Hypothyroidism• Race (Blacks vs. Caucasians) • Nephrotic syndrome/chronic renal failureTiming of test • Biliary tract obstructionBehavioral Drug Therapy:• Diet • Amiodaron – on thyroid profile• Obesity • Diuretics –on pleural fluid• Smoking • Propanolol• Alcohol intake • Oral contraceptives• Caffeine intake • Prednisolone-on immune• Exercise markers• Stress
  13. 13. Timing of test• Hepatitis virus• Dengue serology• Cardiac enzymes• Pencreatic enzymes• Widal test
  14. 14. • Pregnancy• Specimen Collection & Handling – Specimen obtained from wrong patient* – Specimen mix-up* – Nonfasting vs. fasting (12 h)• Anticoagulant: – EDTA – Heparin• Capillary vs. venous blood• Hemoconcentration (eg, use of a tourniquet)• Specimen storage (@ 0–4 C for up to 4 days)
  15. 15. Non-specific laboratory abnormalities in thyroid dysfunctionThyrotoxicosisSerum enzymes – Raised alanine aminotransferase, γ-glutamyl transferase (GGT), and alkaline phosphatase from liver and bone• Raised bilirubin• Mild hypercalcaemia• Glycosuria – Associated diabetes mellitus – Lag storage glycosuriaHypothyroidismSerum enzymes – Raised creatine kinase, aspartate aminotransferase, lactate dehydrogenase (LDH)• Hypercholesterolaemia• Anaemia – Normochromic normocytic or macrocytic• Hyponatraemia
  16. 16. Analytic• Equipment malfunction 7%-13%• Sample mix-ups/interference• Undetected failure in quality control• Procedure not followed• Can be RANDOM or SYSTEMIC
  17. 17. Post-Analytic• Failure in reporting 18.5%-47%• Erroneous validation of analytical data• Improper data entry
  18. 18. •This was Captain E. J. Smiths retirement trip. All he had to do was get to New York in record time•Captain Smith ignored seven iceberg warnings from his crew and other ships•If he had called for the ship to slow down then maybe the Titanic disaster would not have happened
  19. 19. •About three million rivets were used to hold the sections of the Titanic together•They were made of sub-standard iron
  20. 20. Bruice Ismay•Wanted to show that they could make a six-day crossing•To meet this schedule the Titanic could not afford to slow down•It is believed that Ismay put pressure on Captain Smith to maintainthe speed of the ship
  21. 21. 1. Titanic had sixteen watertight compartments.2. Compartments did not reach as high as they should have done.3. The White Star Line did not want them to go all the way up becausethis would have reduced living space in first class.4. If Mr Andrews, the ships architect, had insisted on making them thecorrect height then maybe the Titanic would not have sunk.
  22. 22. The final iceberg warning sent to Titanicwas from the Californian.Captained by Stanley Lord, she hadstopped for the night about 19 miles northof Titanic.At around 11.15, Californians radiooperator turned off the radio and went tobed.
  23. 23. • “Good judgment comes from experience, and experience comes from bad judgment.” ― Rita Mae Brown THANK YOU

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