1. Microbiology Test Results: What do they mean?
Christie Massen M.S., MLS(ASCP)
Microbiologist III – QA/CLIA Coordinator
North Dakota Department of Health
Division of Laboratory Services - Microbiology

2. Objectives
Upon completion of this presentation, participants will be able to:
Summarize various microbiological testing methods.
List the components of a laboratory report.
Interpret various microbiology test results.
Summarize antibiotic susceptibility testing and results.
Compare various serological test results.

3. Infectious Diseases
Bacterial
Viral
Fungal
Parasitic

4. Supporting Laboratory Results
Viral
Identification of virus
Normal or Decreased WBC Count
Increased Lymphocyte Count
Parasitic
Identification of parasite
Increased Eosinophil Count
Bacterial
Identification of bacteria
Increased WBC Count
Increased Neutrophil Count
Left-shift in Neutrophil Cell Line
Increased CRP
Increased Sed-Rate
Fungal
KOH Prep Test
Identification of fungal elements

5. Laboratory Reports

6. Bacterial Culture Grow and isolate bacteria Various media
Identify a pathogen
Pros
Identify the isolate
Very specific
Cons
Lengthy
Normal flora

7. Biochemical Testing

8. Identification

9. Antibiotic Susceptibility Testing
Determine antibiotic susceptibility or resistance

10. Antibiotic Susceptibility Testing

11. Case 1

12. Case 1: Report

13. Case 2

14. Case 2: Report

15. Modified Hodge Test Purpose: Interpretation:
Detection of carbapenemase production in identified organisms
Interpretation:
Positive
Clover leaf-like indentation
along the streak line
Negative
No growth along the streak line

16. Case 3

17. Case 3: Report

18. Virology

19. Virology Culture
Cytopathic Effect (CPE)
Culture
Molecular

20. Case 4

21. Case 4: Report

22. Parasitology & Mycology
Direct Examination
Macroscopic and Microscopic

23. Molecular Testing DNA Probes DNA sequencing
Nucleic acid sequences (16s)
Whole genome sequencing
Nucleic Acid Amplification Testing (NAAT)
Polymerase Chain Reaction (PCR)
Ligase Chain Reaction (LCR)
Transcription Mediated Amplification (TMA)

24. PCR Developed in 1985 First NAA method How it works:
DNA Polymerase replicates the target DNA molecules
RNA can be replicated
Heat and cool cycles utilized
DNA Primers hybridize the target and initiate polymerization of new DNA Molecules
End product: Billions of copies of the target DNA
Read for presence of DNA target

26. Immunology Test Methods
Detects:
Antigens
Antibodies
Test Methods:
Agglutination
Nephlometry
Double Diffusion
Radial Immunodiffusion
Electrophoresis
Western Blot
Flocculation
ELISA
Immunoflorescence assay
Radioimmunoassay

27. Antibody Review

28. Antibody Review

29. Case 5

30. Case 5: Report

31. Case 6

32. Case 6: Report

33. Case 7

34. Case 7: Report

35. Case 8

36. Vaccine Preventable Disease Case 8: Report

37. Questions?

38. References
Kiser, K.M., Payne, W.C., & Taff, T.A. (2011). Clinical Laboratory Microbiology: A Practical Approach. Upper Saddle River, NJ: Pearson Education.
Amjad, A., Mirza, I.A., Zia, F. (2011). Modified Hodge test: A simple and effective test for detection of carbapenemase production. Iran Journal of Microbiology. Retrieved from:
New Directions in Molecular Testing: An Educational Guide for Clinical Laboratory Professionals. Gen-Probe Inc. Retrieved from: