1. Deciphering TB Lab Reports
Jessica Gentry
Tuberculosis Laboratory Supervisor

2. Laboratory Regulation
Laboratories performing diagnostic testing on human patient specimens are regulated by CLIA: Clinical Laboratory Improvement Amendments Regulations establish quality standards for laboratory testing performed on specimens from humans, such as blood, body fluid, and tissue, for the purpose of diagnosis, prevention or treatment of disease, or assessment of health. The purpose is to ensure high-quality testing.

3. Laboratory Regulation
Examples of CLIA regulations:
Qualified, trained personnel performing testing
Laboratory inspections/audits
Enrolled in Proficiency Testing
Laboratory director overseeing testing
Written procedures for testing
Requirements for lab reports

4. Lab Reports Are Difficult to Read…
Different tests performed by different laboratories
PCR vs. probe vs. NAAT
Use of abbreviations
Inconsistent terminology
Multiple dates—collection date, test date, report date
Formatting
Results not listed in chronological order
Results from multiple laboratories on a single report
Results moved through a variety of LIMS systems

5. What’s on a Lab Report? Laboratory Information Patient Information
Specimen Information
Lab Testing Performed
Results Interpretation

6. Laboratory Information
Laboratory Name
Physical Address
Laboratory Medical Director
CLIA Certificate Number
Referral Laboratory Information
Department
Mycobacteriology
Tuberculosis
AFB Lab
Microbiology

9. Patient Information Required: Two patient identifiers, typically:
Patient Name
Unique Patient Identifier (MRN)
Date of Birth
Optional:
Age
Gender
Race/Ethnicity
Address

11. Specimen Information Specimen Source—sometimes listed as “site”
Pulmonary (Respiratory): Sputum, bronchial
Extrapulmonary: Urine, lymph node, CSF, tissue, etc.
Descriptive modifiers sometimes added—Induced or expectorated sputum, tissue location, RUL, etc.
Collection Date
Received Date
Accession Number/Specimen ID/Lab Number

15. Laboratory Tests Test Performed Test Result Normal vs. Abnormal
Interpretation
Units of Measurement
Qualitative (QL) vs. Quantitative (QN)
Date Test Reported

16. AFB Smear Microscopy Acid Fast Bacillus (AFB)
Acid Fast Bacilli, Acid Fast Bacteria
Digested, Concentrated, or Unconcentrated Smear
AFB Stain
Fluorescent
Fluorochrome
Auramine O-phenol

17. AFB Smear Microscopy AFB Negative
No Acid Fast Bacilli seen/observed on smear
AFB Positive
Acid Fast Bacilli seen/observed/found on smear
<1/field, 1-10/field, >10/field, >50/field
1+ (few), 2+, 3+, 4+ (many)
Rare, Few, Moderate, Many

21. Molecular Assays Assays that detect genetic material (DNA) of MTBC:
Polymerase Chain Reaction (PCR)
DNA Probe
MTB-RIF
Nucleic Acid Amplification Test (NAAT)
Negative, Not Detected
Positive, Detected
Testing can be in the specimen or culture
Assays can also look for other mycobacteria—M. avium complex, M. kansasii, M. gordonae

24. Molecular Detection of Drug Resistance
Detection of mutations associated with drug resistance
Assays
Pyrosequencing
Sanger Sequencing
Gene Xpert MTB/RIF
Whole Genome Sequencing (WGS)
Results
Detected vs. Not Detected
Mutation Present vs. Mutation Absent
Cepheid GeneXpert Cartridge

28. Culture Results
AFB culture is typically performed in tandem with an AFB smear
Test names: AFB Cx, AFB Cx + Stn, AFB Identification (ID)
Preliminary results may be reported at 2 wks, 4, wks, etc.
Culture negative—usually reported at 6 wks
Culture positive
Organism isolated, Organism ID
MTBC, MTB, Mycobacterium tuberculosis
Method used for ID—PCR, probe, MALDI-TOF, etc.

32. Antibiotic Susceptibility Testing
Antibiotic tested
Critical concentration or MIC (Minimum Inhibitory Concentration)
Sometimes multiple levels per antibiotic
Result/interpretation
R=Resistant
S=Susceptible, Sensitive
Method used
Broth (MGIT)
Agar Proportion (AP)

36. Conclusions Different labs use different test methods
All labs report results differently
Labs like to use abbreviations
BUT—understanding what type of information is included in a lab report and knowing the keywords to look for can be very helpful
ALSO—If you have questions, call the lab and ask!

37. Questions?
Jessica Gentry Tuberculosis Laboratory Supervisor Indiana State Department of Health Phone: (317)