533566077
Document type: SOP
Document code: TB 02-10
INTER-LABORATORY TESTING
Confidentiality: none
TABLE OF CONTENTS
1.
PURPOSE ...................................................................................................................... 2
2.
SCOPE ........................................................................................................................... 2
3.
RESPONSIBILITIES....................................................................................................... 2
4.
CROSS-REFERENCES ................................................................................................. 2
5.
PROCEDURE ................................................................................................................. 2
5.1. Microscopy ................................................................................................................................... 2
5.2. Drug Susceptibility Testing ........................................................................................................... 4
6.
CHANGE HISTORY ....................................................................................................... 5
This SOP template has been developed by FIND for adaption and use in TB laboratories
Release date: ddMMMyy
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1. PURPOSE
This procedure describes inter-laboratory testing of samples or specimens at the
___________________TB Laboratory and the National TB Reference Laboratory (NTRL). The
testing forms part of the quality assurance activities of both organizations in order to ensure
accurate and consistent results from TB diagnostic testing.
2. SCOPE
This SOP applies to all personnel working in the ___________________TB Laboratory and the
NTRL.
3. RESPONSIBILITIES
The Head of the ___________________TB Laboratory and the Quality Manager of the NTRL are
jointly responsible for organization and performance of procedures described in this SOP.
4. CROSS-REFERENCES
See:
Document Matrix_TB 01-01_V1.0.doc
Location:
Refer to SOPs listed under General Procedures (TB 02)
5. PROCEDURE
5.1. Microscopy
Inter-laboratory testing for sputum smear microscopy will consist of blinded re-checking of specimens
from each laboratory (i.e. ___________________TB Laboratory will re-check NTRL and NTRL will recheck ___________________TB Laboratory slides).
Re-checking will be done on a monthly basis, with four Ziehl Neelsen (ZN) and four Fluorescent
Microscopy (FM) slides being re-checked from each laboratory. Slides will be sampled during the first
week of the month, with all slides being read the previous month being sampled. All slides prepared
and read by the ___________________TB Laboratory and NTRL will be stored in such a manner as
to allow sampling for the purposes of re-checking. Sampling will be performed by NTRL Quality
Manager according to the following procedure:
Note: a different calculation for sampling will be required for the ___________________TB
Laboratory and NTRL based on the number of slides processed by ZN and FM by each lab. Perform
a separate calculation for each method (ZN and FM) and for each laboratory):
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Sampling interval = Number of slides in previous month / sample size (4)
Starting point = 1 to (sampling interval – 1)
The starting point will be selected by the NTRL Quality Manager at the time of sampling.
Example: If the NTRL processes 400 FM slides the previous month, sampling interval =
400/4 = 100. Starting point can be between the 1st and 99th slide. If starting point is chosen as
3, then FM slides number 3, 103, 203 and 303 will be selected for re-checking.
The NTRL Quality Manager will record the original slide numbers selected on the Inter-laboratory
Microscopy Re-checking Form (which is to be kept as confidential from all laboratory staff, with the
exception of Head of the ___________________TB Laboratory). NTRL Quality Manager will blind the
specimens and designate a new code to each slide. The code will also be recorded on the
Microscopy Re-checking Report.
Use:
Microscopy Re-checking Report_form.doc
Location:
Four blinded ZN slides and four blinded FM slides from NTRL will be provided to
___________________TB Laboratory for reading. A form containing only blinded codes will be
provided to ___________________TB Laboratory for the purposes of recording of results. Similarly,
four blinded ZN slides and four blinded FM slides from ___________________TB Laboratory will be
provided to NTRL personnel for reading. A form containing only blinded codes will be provided to
NTRL for the purposes of recording of results. No re-staining will be performed prior to reading of
slides. Interpretation of smear results will be according to WHO / IUATLD guidelines.
See:
Ziehl Neelsen Microscopy_TB 04-01_1.0.doc
Fluorescence Microscopy_TB 04-02_1.0.doc
Location:
Results will be recorded on the following form:
Use:
Microscopy Re-checking Results_form.doc
Location:


The NTRL Quality Manager will request results to be provided on the designated form within a
maximum seven days from the time of delivery to each laboratory.
The NTRL Quality Manager will compile reports of the re-checking once all results have been
reported and email or send the printed version of the completed forms to the Head of the
___________________TB Laboratory.
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

The Head of the ___________________TB Laboratory and the NTRL Quality Manager will jointly
review results and NTRL Quality Manager will schedule a joint review meeting between the
___________________TB Laboratory and the NTRL personnel.
Corrective and preventive measures will be implemented and documented jointly by the NTRL and
___________________TB Laboratory.
5.2. Drug Susceptibility Testing
NTRL routinely performs DST using MGIT 960 and Lowenstein-Jensen proportion methods.
___________________TB Laboratory routinely performs DST using MGIT 960 and Genotype
MTBDRplus (Line probe assay). Each organization will test the proficiency panels provided as part of
this Inter-Laboratory Testing programme with both methods they routinely perform.
Although the nature of the isolates provided will be unknown, one panel will be used for testing by both
methods in each laboratory.
Inter-laboratory testing for DST will be performed every 6 months, in August and February. Each
round of testing 3 isolates will be provided to each laboratory. Choice of panel strains will be jointly
decided by the Head of the ___________________TB Laboratory and the NTRL Quality Manager
according to a confidential DST Panel Selection Table. This table will only be accessible to Head of
the ___________________TB Laboratory and the NTRL Quality Manager.
See:
DST Panel Selection MMMyy_form.doc
Location:
Three isolates will be provided to NTRL and ___________________TB Laboratory, along with a hard
copy of the Inter-laboratory DST Results form.
Use:
Inter-Laboratory DST Results_form.doc
Location:




All isolates will be provided as fresh sub-cultures on Lowenstein-Jensen medium. Dates of subculturing and sources of isolates will be recorded by the NTRL Quality Manager. Isolates should
be subjected to DST as soon as possible to avoid the need for further sub-culturing prior to
testing.
For MGIT DST and LJ DST, first line DST to SIRE (streptomycin, isoniazid, rifampicin and
ethambutol) will be carried out. Genotype MTBDRplus testing gives results of rifampicin and
isoniazid resistance.
All results of testing should be recorded on the Inter-Laboratory DST Results form (see above for
location), and completed forms will be returned to NTRL Quality Manager.
The NTRL Quality Manager will request results to be provided on the designated form within a
maximum 8 weeks from the time of delivery to each laboratory. The NTRL Quality Manager will
compile reports of the re-checking once all results have been reported and email the completed
forms to the Head of the ___________________TB Laboratory.
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

The Head of the ___________________TB Laboratory and NTRL Quality Manager will jointly
review results and the NTRL Quality Manual will schedule a joint review meeting between the
___________________TB Laboratory and NTRL personnel. Corrective and preventive measures
will be implemented and documented jointly by NTRL and the ___________________TB
Laboratory.
Comparison of MGIT results will be the primary objective, and discrepancies of the other methods
is possible. Where discrepancies exist (e.g. between MTBDRplus and MGIT DST) these will be
discussed and further testing may be performed to resolve discrepancies if considered necessary.
6. CHANGE HISTORY
New version #
/ date
Old version #
/ date
No. of
changes
Description of changes
Source of
change request
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