# Presentation: 750755

## External QA for TB- Botswana Data

- Michael Mwasekaga
- Principal Medical Lab Technologist
- National TB Reference Laboratory, Gaborone - Botswana

## Republic of Botswana        

- Landlocked in Southern Africa
- Population: 1.7 million
- Laboratory services integrated within the Public Health Services.
- TB incidence rate (2001): 620/100,000 population
- 49 Medical Laboratories in the Country (1 Lab per 35,000 population).

## TB LABORATORY NETWORK

- NHL

- NTBRL

- Smear
- Culture
- Identification
- DST
- TB research
- EQA for TB

**District Lab**

**Primary Lab**

**Mission Lab**

**Mines Lab**

**Others**

**Reference Lab (North)**

- AFB Smear only

- AFB Smear & Culture only

## Laboratory Resources:

- Labs staffed with qualified Technicians
- Adequate financial resources
- Adequate supplies
- Supplies source: Centralized
- Effective Communication channels (Telephone, Fax, Email, Road, Air)
- Functioning Equipment (Microscopes)

## EQA for TB Methods:

| Method | Advantages | Disadvantages | Uses |
| --- | --- | --- | --- |
| On-site
Supervision | Observation of actual work

Identify causes of errors |  Labour intensive
 Costly | Supervisory visit

Monitor quality improvement measures |
| Panel Testing   | Rapid response countrywide

Identification of faulty equipment | Does not measure
  routine performance
May not be motivating
 to improve daily
 performance | First step for 
  EQA
Rapid assessment of gross deficiencies |
| Blinded Rechecking | Reflect Lab routine performance | Heavy workload (Centre)
Bias if not blinded
Staff availability | Standard for Monitoring Lab performance |

## EQA for TB in Botswana:

- Program started in 2002
- Main Objectives:
- To continuously monitor and improve the efficiency and reliability of the AFB Smear microscopy in the country.
- To establish inter-laboratory comparability in agreement with a reference standard.

## AFB Smear Microscopy:

- Important tool for TB case finding and in monitoring patient’s response to chemotherapy.
- In 2002, Total of 64,500 Direct AFB smears were examined in Govt. Labs.
- EQA  by Panel Testing method.

## Panel Testing Method:

- 19 Labs participated (51%)  - 1 Reference, 6 Districts, 11 Primary & 1 Clinic Labs).
- Five (5) stained AFB smears sent with Chief Technician / Quality Manager.
- Microscopists examined the slide independently (Total = 31 Technicians).
- NTBRL assessed the results & sent feedback.

## Scoring System used:

- Set of 5 slides.
- Each slide worth 20 points.
- Total possible score was 100:
- Each correct slide scores 20
- Each incorrect slide scores 0
- Passing score 80

## True Positive / True Negative Results:

**True Positive / True Negative Results:**

## Results... cont:

## Results... cont:

## Results... cont:

|  | Reference Laboratory |  |  |  |
| --- | --- | --- | --- | --- |
|  |  | Pos | Neg | Total |
| Participating Laboratories | Pos | 120 | 1 | 121 |
|  | Neg | 4 | 30 | 34 |
|  | Total | 124 | 31 | 155 |

- False Negative = 11.8%, False Positive = 0.83%

## Discussions:

- In a laboratory where more than one Technician participated, the lab result was the average of the individual scores for that lab.
- Panel Testing does not measure the routine laboratory performance and therefore, use of average score does not truly reflect the actual lab performance. However, in this exercise it was used to obtain data for inter-laboratory comparisons.

## Discussions........ cont:

- Performance of laboratories was found to be satisfactory (scored 80% or above).
- However, a false negative rate of 11.8% and the fact that 26% of Technicians used a Smear Grading System other than the one in the current SOPs, was an indication that a re-training was necessary.
- A workshop was conducted after this exercise.

## Limitations:

- The Panel size (5 slides) was below the globally recommended size of 10 slides.
- The exercise did not include unstained smears and therefore, it did not address the quality of smear preparation and staining.
- The results were also not a representation of the routine performance of participating laboratories.

## Conclusions:

- This was an initial exercise of EQA for TB in Botswana.
- The exercise did help in the identification of individuals who needed re-training.
- It also highlighted some limitations in the current program.
- On-site visits by the reference lab, regular feedback on individual results, motivation of technicians and re-training will allow for gradual improvement in the quality of the microscopy network in the country.

## Recommendations:

- Frequency of Panel Testing should be increased to twice a year and extended to all all laboratories doing AFB Smear Microscopy.
- Blinded Rechecking of slides should be implemented in order to establish the true individual laboratory performance.

## THANK YOU.