Title: Implementation of an AFB Smear Microscopy External Quality Assessment Program in Zambia GABERONE BOT
1Implementation of an AFB Smear Microscopy
External Quality Assessment Program in
ZambiaGABERONE BOTSWANA29, July 2003
- BWALYA RUTH TEMBWE
- PRINCIPAL SCIENTIFIC OFFICER
- CHEST DISEASES LABORATORY
- (NATIONAL REFERENCE LABORATORY FOR TUBERCULOSIS)
- LUSAKA, ZAMBIA
2Tuberculosis (TB) in Zambia
- 512 TB cases per 100,000 population (10.6 total
pop.) - Direct AFB sputum microscopy
- - most cost effective for diagnosis and
monitoring treatment - 154 AFB smear microscopy centers
- National Reference Laboratory (CDL) in Lusaka
- No previous organized system for assuring the
quality of TB smear results in laboratory network
3Map of Zambia showing 9 Provinces
4Zambia TB Microscopy National Action Plan for
2002 2003
- National Action Plan for AFB Smear Microscopy
- external quality assurance (EQA) developed
June 2002 - Central Board, MoH, CDL and Province Laboratory
Managers - Onsite laboratory evaluation form modified by lab
managers - Based on the External Quality Assurance
Guidelines developed by International Work Group
- Support for EQA from CDC also JICA and WHO
http//www.aphl.org/Infectious_Diseases/EQA.cfm
5Components of AFB Microscopy External Quality
Assurance
- (1) On-site evaluation of the microscopy
laboratory - -microscopes, registers, reporting
results, techniques, etc. - (2) Panel testing (PT) of technicians who read
and report AFB smears - -competency in detecting and
quantification of AFB in smears - (3) Blinded rechecking of smears randomly
selected by a statistical method - -determines of errors in a statistical
sample of slides read in a laboratory -
6Implementation of EQA Activities
- In phases starting with 9 provincial hospital
laboratories - On-site evaluation was done consecutively with
PT in each province hospital laboratory
(September 2002 to January 2003) - Province Mangers will conduct onsite evaluation
and PT in their respective district and rural
laboratories
7 Implementation of Panel Testing
- CDL determined the AFB technicians in each
Province Hospital Laboratory for PT slide
preparation - Communication with Public Health Directors
regarding EQA activities - Preparation of schedule for onsite laboratory
evaluation and Panel Testing (PT) of AFB
microscopists in each province - Technical support and consultation with
CDC-Atlanta on preparation and validation of
slides to be used for PT
8Implementation of EQA Activities (continued)
- Batches of PT smears developed at CDL based on
EQA guidelines - Smears were negative 1-9 1 2 and 3 AFB
- AFB in smears validated at CDL, UTH CDC-Atlanta
- 10 slides per technician 5 stained at CDL and 5
un-stained to be stained by technicians - Successful completion of PT challenge was at
least 80 score
9Onsite Evaluation and PT
- Total time involved was at least three days for
each laboratory - Courtesy calls to Province Health Director and
Laboratory Administration - Orientation of Laboratory staff to PT and onsite
evaluation process -
- Panel testing about three hours
- 1½ - 2 hours for 10 slide test
evaluation - 5 slides pre-stained at CDL 5 stained
by each technician to be tested - On site evaluation, about 2 hours
- Equipment, procedures and laboratory register
assessed - Corrective actions discussed with technicians,
about 1 hour - Scoring PT and documentation of onsite visit
results - Travel time one day
10Province Panel Test Results
- PT success rate 52 at province laboratories
- Types of errors high false negative and
quantification were most common - PT and onsite exercises were received positively
by managers and technical staff - Staff and managers were receptive to discussing
opportunities for improvement - Communication - a very important factor !!!
11Panel Test and Onsite Evaluation Workshop
- 3 day re-training workshop
- Re-training on quantification of AFB smears
- Appropriate preparation of stain reagents
specimen labeling, etc. - Attention was given to equipment, reagent and
technical needs in the laboratory - New microscopes had been distributed to some
laboratories others were still in need - Weigh balances were needed
- More detail on Zambia PT to be presented at
IUATLD Meeting (Paris, France - October 2003) - Participants were also oriented to the Rechecking
program
12Implementing Blinded Rechecking
- Determine of smears performed in each
laboratory - Determine the number of positive smears in the
laboratory - Slide positivity rate
- Distribute slide boxes to archive slides
consecutively for one quarter - Storage of slides began on 1st April 2003
- For ease of random collection of slides
- - each sample received in the laboratory
is given an - individual number
- May 2003 - supervisory visit to check on the
progress of slide storage and management of
laboratory register
13Initiation of Rechecking Program
- First supervisory findings
- Some laboratories were following the recommended
procedures - Two laboratories had not yet started advised to
commence on 1st July - One laboratory was not grading the positive
smears - Random collection of smears for rechecking to
begin on 10th July - The numbering in the register should be carefully
checked as some numbers are missed e.g., after
1099 the next number was 2000 instead of 1100.
14Resources for EQA Activities
- Adequate number and dedicated staff at NRL
- Microscopes (some centers have one for all lab
work) spare bulbs - A reliable mode of transportation/vehicle and
funds for food/lodging - Computer for preparation of forms and
communications - Slide boxes to store 3-4 month volumes of slides
per laboratory - AFB Microscopy EQA Guideline for International
Laboratories - Consultation with others involved in AFB
Microcopy EQA activities
15Acknowledgements
- Financial and technical support
- Centers for Disease Control and
Prevention-Zambia - Japanese Inter Cooperation Agency
- World Health Organization
- Ireland AID
-
- Consultants
- Centers for Disease Control and Prevention,
Atlanta, GA (USA) - Dr. John Ridderhof
- Dr. Bereneice Madison