Clinical Chemistry

• CLINICAL CHEMISTRY SECTION - most automated area of the laboratory
• AREAS IN CLINICAL CHEMISTRY

  • General or automated chemistry
  • Electrophoresis
  • Toxicology
  • Immunochemistry
• Serum - collected in gel barrier tubes,
• Hemolyzed specimens – appear red because of the release of hemoglobin from rbc's
• Icteric specimens – appear yellow because of the presence of excess bilirubin
• Lipemic specimens – are cloudy [gelatin-like] because of increased lipids
• Serum separator tubes - contain an inert gel that prevents contamination of the specimen by RBCs or their metabolites.
• ROUTINE SAMPLES

  • tests that are ordered by the health-care provider to diagnose and monitor a patient’s condition.

  • usually collected early in the morning but can be collected throughout the day during scheduled “sweeps” (collection times) on the floors or from outpatients
• ASAP SAMPLES - The response time for the collection of this test sample is determined by each hospital or clinic and may vary by laboratory tests.
• STAT SAMPLES

  • highest priority and are usually ordered from the emergency department or for a critically ill patient whose treatment will be determined by the laboratory result.
  • The sample must be delivered to the laboratory promptly and the laboratory personnel notified.
• Stat - means the sample is to be collected, analyzed, and results reported immediately.
• FASTING SAMPLES - The patient must only have refrained from eating

  and drinking (except water) for 12 hours
• TIMED SAMPLES

  • Hormones [specific time; follow instructions]

  • Requisitions are frequently received requesting that blood be drawn at a specific time.

  • Phlebotomists should arrange their schedules to be available at the specified time and should record the actual time of collection on the requisition and sample tube.
• GLUCOSE TOLERANCE TESTS - or the diagnosis of diabetes mellitus and gestational diabetes [increase in blood sugar during pregnancy:
• 2-HOUR ORAL GLUCOSE TOLERANCE TEST - recommended method for the diagnosis of diabetes mellitus.
• ONE-STEP METHOD

  • Utilizes the same procedure as the diagnostic OGTT used to diagnose diabetes mellitus [glucose drink given only once]
• TWO-STEP METHOD - requires the patient to receive two tests.
• LACTOSE TOLERANCE TEST - evaluates a patient’s ability to digest lactose, a milk

  sugar.