Module%202

1
Module 2

• The Diagnostic Testing Process

2
Case Scenario 1
Photo by Elizabeth Wantuch,MD

• In order to make their daily work-flow smoother,
  a resident and intern on a busy inpatient service
  include the following order when they admit any
  patient
• Draw daily CBC, CMP, PT, PTT, Magnesium, Ionized
  Calcium and Phosphorous x 30 days
• Comment on this approach to their care of
  patients.

3
Case Scenario 1Discussion

• 4 major roles for laboratory tests in patient
  care
• Diagnosis of disease
• Monitoring of disease, therapies, interventions
• Screening for disease
• Research

4
Case Scenario 1Discussion

• The resident and intern (though perhaps
  well-intentioned) are not properly utilizing
  laboratory testing and the clinical laboratory
• They are not ordering specific laboratory tests
  based on clinical questions
• AND in doing so they are
• Increasing the cost of healthcare
• Contributing to the development of iatrogenic
  anemia
• Leading to potentially unnecessary work-up if any
  errors in the diagnostic testing process occur

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Laboratory testing begins and ends with patient
care

• Clinician develops a clinical question
• Specific laboratory test is selected
• Test is ordered
• Specimen is collected
• Sample is prepared for analysis
• Sample is analyzed
• Result is verified
• Result is reported
• Test result is interpreted in context of clinical
  scenario
• Action is taken
• Patient care is affected

Image by Theresa Kristopaitis, MD
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Diagnostic Testing 3 Phases

• The diagnostic testing process can be separated
• into three phases
• Preanalytic phase
• Analytic phase
• Post analytic phase
• Variables that may affect proper interpretation
  of test results are present in each phase.
• Test result changes due to clinical factors must
  be interpreted in consideration of these
  variables.

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• Clinician develops a clinical question
• Specific laboratory test is selected
• Test is ordered
• Specimen is collected
• Sample is prepared for analysis
• Sample is analyzed
• Result is verified
• Result is reported
• Test result is interpreted in context of
• clinical scenario
• 10. Action is taken
• 11. Patient care is affected

PREANALYTIC Phase
ANALYTIC Phase
POSTANALYTIC Phase
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Why is this important?

• When a physician orders a lab test and receives a
  test result, there are a multitude of factors
  (variables) that could (and usually should) be
  considered in interpreting the test result

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• In the upcoming modules, we will further explore
• The Preanalytic testing phase
• The Analytic testing phase
• The Postanalytic testing phase
• The process of establishing Reference (normal)
  values

10

• Proceed to Module 3 - Preanalytic Phase of
  Laboratory Testing