Quality

From Libre Pathology
Revision as of 15:06, 22 January 2012 by Michael (talk | contribs) (expand IHC section)
Jump to navigation Jump to search

Quality, in pathology, has got a lot of attention lately because there have been high profile screw-ups that lead to significant harm.[1]

Analysis

Overview

Quality issues are examined a number of different ways, e.g. root cause analysis, failure mode and effects analysis (FMEA).

A common way to break down error analysis is:

 
 
 
 
 
 
 
 
Errors in pathology
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Pre-analytical errors
 
 
Analytical errors
 
 
Post-analytical errors

Failure-potential analysis

Adapted from Ullman:[2]

  1. Identify potential individual failures.
  2. Identify the consequences of those failures.
  3. Identify how the individual failures can arise.
  4. Identify the corrective action.

General error analysis

  • Pathology errors happen any time from when the lab gets the specimen until after the report is issued.

When errors happen:

  • Work-up problem.
    • Where did it occur?
  • Talk to the clinician.
    • If it is a critical diagnosis contact most-responsible physician immediately... if they are unreachable call physician on-call for the most-responsible physician... if the patient is out-of-town you may have to coordinate with the emergency department.
  • Talk to the chief of pathology.
  • Incident report.
  • Reconstruct error.
    • Was it a specimen mix-up?
      • Is there another error?
  • Amend report(s).
  • Remedy source of error.

Pre-analytic errors

  • Container mix-up - pre-lab & in-lab.
  • Block mix-up.
  • Slide mix-up - labels wrong.
  • Poor quality slides (fixation, processing, staining).

Analytic errors

  • Interpretation wrong.
    • Difficult case.
    • Technical factors (quality of slides).

Post-analytic errors

  • Wrong case signed-out.
  • Filing problem.
  • Interpretation of report problem (poorly written, bad interpretation).

Error reduction

Various strategies can be employed:[3]

  • Training of staff - on error handling.
  • Computer order entry.
    • Avoid duplication fatigue.
    • Quick correlation with several identifying features.
      • Full name, sex, date of birth -- these all appear when one opens a case.
  • Barcode use.
    • Avoid transcription errors.
  • Clinical information entry required.
    • Allow correlation with test.
      • The interpretation may differ if the history says "screening coloscopy" versus "large cecal mass, anemia and weight loss".

Other strategies:

  • Statistical process control.

Sources of error

  • "Human error".
    • Training.
    • Work flow.
  • Process gaps.
    • Process control.
    • Lack of redundancy.

Biopsy size

Very small tissue fragments are associated with a decreased diagnostic yield and an increased diagnostic uncertainty.

Immunohistochemistry

Work-up of suspected IHC problems:

  • Review controls (internal and external).
    • Isolated to case vs. larger problem?
      • Discuss with lab/make other pathologists of the issue.
  • Repeat test - to identify the cause.

IHC process:

  1. Ischemia time - warm ischemia, preparation of specimen.
  2. Fixation - under, over, defective fixative, not enough fixative.
  3. Processing prior to antibody binding, usu. heating (antigen retrieval).
  4. Antibody-antigen binding.
  5. Reporter molecule binding.
  6. Counterstaining.
  7. Interpretation.

Notes:

  • Problems can arise at any step.

Classification of IHC tests

IHC tests are classified in a paper by Torlakovic et al.:[4]

  • Class I:
    • Adjunct to histomorphology.
    • Examples: CD45, S-100.
  • Class II:
    • Considered independent of the other information in the pathology report; thus, cannot be derived from other information in the report.
    • Used directly for treatment decisions.
    • Examples: ER, PR, HER2.

The implication of irregularies in the different classes are different. Problems in Class II tests are potentially more severe, as there is no internal control.

See also

References

  1. URL: http://www.attorneygeneral.jus.gov.on.ca/inquiries/goudge/index.html. Accessed on: 1 March 2011.
  2. Ullman, David G. (1997). The mechanical design process. Toronto: McGraw-Hill Companies Inc.. ISBN 0-07-065756-4.
  3. Fabbretti, G. (Jun 2010). "Risk management: correct patient and specimen identification in a surgical pathology laboratory. The experience of Infermi Hospital, Rimini, Italy.". Pathologica 102 (3): 96-101. PMID 21171512.
  4. Torlakovic, EE.; Riddell, R.; Banerjee, D.; El-Zimaity, H.; Pilavdzic, D.; Dawe, P.; Magliocco, A.; Barnes, P. et al. (Mar 2010). "Canadian Association of Pathologists-Association canadienne des pathologistes National Standards Committee/Immunohistochemistry: best practice recommendations for standardization of immunohistochemistry tests.". Am J Clin Pathol 133 (3): 354-65. doi:10.1309/AJCPDYZ1XMF4HJWK. PMID 20154273.