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DOTS Directly Observed Treatment, Short

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DOTS Directly Observed Treatment, Short
Module
PROBLEM-ORIENTED
SUPERVISION
AND PROBLEM SOLVING
1
Content Overview
• Scope of problem-oriented supervision
• Problem-oriented supervision as the aim of the
•
EQA program
Problem identification and solving
•
•
•
•
Many (or almost all) HFP as well as HFN
False positives
False negatives
Quantification errors
• Laboratory indicators
2
Scope of Problem-Oriented Supervision
•
Checking each and every item and procedure is very
time consuming:
• the need to observe the routine work for most of a day
•
•
Alternative: screening for a few important points based
on earlier findings
Opposite to screening the whole process
• only specific areas of the laboratory work are targeted for
checks
•
•
Effective time management
Most of it can be done by general TB supervisors
3
Laboratory Register Checks
•
The register should be complete and up to date,
results look plausible
•
Check on the last pages if all sputa arrived have
been entered
•
Check if results of the day before were registered
•
Check with the recent past results if, according to the
WHO revised policies:
• most (but not all) suspects had two smears examined
• detected cases had at least one positive result
4
Laboratory Register Checks (cont.)
•
•
•
Cross-check the TB lab register against the TB patient
register:
• All cases recently detected should be registered for treatment
• Promote writing a note in the lab register:
• the patient register number
• where the detected case was sent for treatment
Cross-check the TB patient register against the TB lab
register:
• assess delay between a positive result and start of treatment
Make counts
• Estimate total workload
• Calculate indicators
5
Looking at Smears
• Macroscopic inspection with the naked eye:
• detect poor smearing and identify deficiencies
• assess quality of staining, i.e. decolorization and
counterstaining
• check identification / labeling of
• sputum containers
• freshly smeared or stained smears awaiting
examination
6
Looking at Smears (cont.)
• Microscopic observation of a few recent
positives:
• assess quality of staining - if the red colour
of AFB is deep and even
• inspect how the microscope functions
Note: smears should be strong positives
and definitely recent ones to avoid a
wrong impression because of possible
fading
7
Blinded Rechecking
Efficiency and Reliability
• The collection of slides kept should be
inspected
• for probable completeness
• conditions of storage (out of sunlight, properly
arranged by number)
• Slides should NOT
• be separated as positives and negatives
• have the result written on them
8
Blinded Rechecking
Efficiency and Reliability (cont.)
• Inquire about
• regularity of sampling and how this is done
• Check feedback preferably by requesting
reports received
• If reports are present:
• check reports for plausibility and results
• In case serious errors were detected in rechecking
• inquire about actions taken and their effectiveness
(“evolution of errors”)
9
Important Issues
•
Blinded rechecking system and on-site supervision
• are complementary to each other
• will function less effectively without each other
•
•
Analysis of laboratory indicators and EQA data will
guide supervisors to focus on those elements which
can be possible sources of errors
Development and observance of algorithms while
investigating of errors will help supervisors to
• find deficiencies
• correct deficiencies
• prevent appearance of errors in future
10
Problem Identification and Solving:
Investigation of Rechecking Errors
11
Investigation of Errors
• Consider:
• types and number of errors detected
• the controllers’ qualitative remarks
 false positive, false negative or both?
 false positives:
 only low, or also high?
 in which numbers?
 false negatives:
 low, high, or both?
 in which numbers?
 quantification errors?
 when interpreting consider if restaining was used or not
12
Many (or almost all) HFP as well as HFN
•
Indicate a serious problem:
•
•
•
•
total lack of training
or unusable microscope
or smears were not examined
Investigation:
examine a 3+ smear with that microscope, to see if it
works properly
request the microscopist to examine a clear-cut positive
and a negative smear with a good microscope, to see if
he/she knows what is AFB
if both are OK: conclude at total neglect, not examined
13
False Positives
•
Just one HFP:
•
administrative error
•
•
•
•
poor slide numbering
transcription error
failure of the controllers to detect AFB
Only LFP
•
limitation of the controls
•
•
•
•
poor reproducibility in this range,
damaged smears...
hazy microscope
confusion regarding recognition of AFB
14
False Positives (cont.)
•
More HFP, with or without LFP
•
•
•
•
•
sloppy administrative procedures
confusion regarding recognition of AFB
no restaining in situations with fading of staining, not
even of discordants
not examining all smears but copying positive results
to the second and/or third smear of a series
rarely contaminated carbolfuchsin stain
15
Investigation of False Positives
•
•
•
Not needed for LFP occurring at low frequency,
similar to other labs and the first controller
Not urgent for a single high false positive
Check the listed result on the rechecking form with
that in the laboratory register:
• same number and result?
• if not: correct all records
• if result/identification is uncertain: exclude the rechecking
result from analysis
16
Investigation of False Positives (cont.)
•
Ask the technician to show the AFB in the false positive
slide with his / her microscope:
• clearly visible?
• if NO: faulty microscope - adjust or repair or replace
microscope
• true AFB?
• if NO AFB but artefacts: educate the technician
• if YES: report controller error to the rechecking coordinator
• rechecking process needs improving?
• recheckers to be replaced?
• if no AFB are seen: restain and re-examine HFP again
• If AFB appeared: fading; need to restain more?
• If NO: damaged smear?
17
Investigation of False Positives (cont.)
•
Look for signs of sloppy administration / identification:
•
•
•
•
•
•
is laboratory register up-to-date?
are sputum examination forms used?
is labeling on sputum pots done consistently?
do results on forms/lists correspond to those in the register?
are isolated positive/scanty results in case series not so rare?
Many LFP:
• check if quantification scale is understood
• if too many LFP:
• check as many recent LFP as possible on the spot, without restaining;
• ask the technician to show what he/she considers to be AFB
18
False Negatives
•
Single LFN
•
•
•
NO investigation
Monitor evolution
Single HFN
•
•
an administrative error; or copying results from
other smears
some smears are not examined: days of
overload
19
False Negatives (cont.)
•
Several HFN, and/or LFN
•
•
•
•
•
•
very thick smears
bad stain or poor staining / poor staining technique
poorly lighted or hazy microscope (due to dirt,
fungus or oil inside, other problems)
contaminated methylene blue or rinsing water
superficial or no examination
very rarely: technician doesn’t know AFB; colour
blindness
20
Investigation of False Negatives
• Look at a full box of smears:
• if many too thick, AFB hard to see: poor smearing
/ less light
• if many too red background: destaining faulty
• if many too dark blue: smearing / counterstaining
faulty
• Look at carbolfuchsin stain poured on a new
slide on the staining bridge:
• can you see the bridge easily? is colour too light?
• If YES: bad carbolfuchsin staining solution, replace
21
Investigation of False Negatives (cont.)
• Examine positive smears with their
microscope
• is light in the microscope less bright?
If YES:
• check correct position of a condenser and
diaphragm
• remove filters (if used)
• if mirror is used: find better place for
examination
• check for heavy fungus growth
22
Investigation of False Negatives (cont.)
•
Examine positive smears with their microscope (cont.)
• hazy view, or complete blur? If YES:
• try to clean eyepieces, condenser, light source and
objectives and check again; replace obviously
damaged parts
• check red staining of AFB in a few recent nonrestained strongly positive smear:
• strong or weak red?
• solidly stained or thin or granular AFB?
23
Investigation of False Negatives (cont.)
• Exclude contamination of methylene blue (only if
rechecked smears were restained)
• repeatedly stain known negative smears, check if
(atypical) AFB appear
• make ZN smears from taps and containers /
glassware used for preparation of solution and
staining: AFB found?
• If contamination is confirmed, exclude the laboratory’s
sample from evaluation
• Check the register for daily workload:
• less than 25 smears on average per technician
involved in ZN microscopy?
24
Investigation of False Negatives (cont.)
• No reason found after all previous checks:
• assume superficial reading to be the cause if false
negatives not so rare and more are LFN
• suspect administrative mistake if exceptional (more
chance to be HFN)
25
Quantification Errors
•
May be caused by:
•
•
•
•
lack of quantification skills or motivation
poor microscope
poor staining solutions or staining procedure
When interpreting, consider:
•
whether the rechecking procedure was used with
or without restaining?
26
Investigation of Quantification Errors
• Lack of quantification skills:
• use a panel for confirmation
• Smears for rechecking were restained, and
quantifications consistently higher for recheckers
(and possibly accompanied by false negatives)
• check staining solutions (and staining procedure if
solutions are good)
• check the microscope (light, sharpness)
(check positive smears without restaining to
differentiate)
27
Investigation of Quantification Errors (cont.)
• Smears for rechecking were not restained and
quantifications consistently higher for recheckers
(and possibly accompanied by false negatives)
• check the microscope (light, sharpness)
• No problem detected: lack of efforts
28
Laboratory Indicators
29
Laboratory Indicators for Sputum Smear
Microscopy: Important Issues
•
•
Are not well known
May not be easily used:
• chance variations / highly seasonal variation of case-finding
• accurate record keeping is needed
• small counts in small laboratories
•
•
•
Can be used as a part of internal quality control
practices
Experts’ assistance is needed to determine the best
indicators for the country
Recording and reporting forms
30
Positives Prevalence of Suspects Smears
•
•
•
Indicates lab quality, but also
• accessibility (financial, geographical)
• selection of suspects
Normal prevalence: 10% ?
• varies ~ NTP: accessibility, other diseases (HIV !)
• varies ~ level of service
• seasonal variations ...
Extract lab quality ?
• compare units at same level
• only gross lab deficiencies may show
31
Monitoring Percent of Positive Suspects Smears (I)
Quality surveillance sputum microscopy
NK 1997
50
Percent positive
45
% pos. suspects
40
35
30
25
20
15
10
5
0
Jan.
Feb.
March
April
May
June
July
August
Sept.
Oct.
Nov.
Dec.
32
Monitoring Percent of Positive Suspects Smears (II)
Quality surveillance sputum microscopy
GO 1997
40
Percent positive
35
% pos. suspects
30
Number of TB suspects examined by sputum smear microscopy x 100
Total number of TB suspects identified
25
20
15
10
5
0
Jan.
Feb.
March
April
May
June
July
August
Sept.
Oct.
Nov.
Dec.
33
Positives Prevalence of Follow-up Smears
•
•
•
Sensitive indicator of lab quality
Normal prevalence may be around 10%
• ~ population: early treatment? MDR-TB? HIV?
• ~ guidelines: no. of smears first 2-3 months?
• ~ correct registration: targets!!
Interpretation of very low prevalence
• superficial reading or bad microscope
• and/or poor staining
34
Positives Prevalence of Follow-Up Smears :
Example of Data Analysis
18
POOR MICROSCOPES, INEFFECTIVE
QUALITY CONTROL, OVERLOAD
16
NUMBER OF CENTRES
14
12
10
8
6
4
2
0
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
% POSITIVE FOLLOW-UP SPUTUM SMEARS
35
Positives Prevalence of Follow-Up Smears:
Example of Data Analysis (cont.)
10
GOOD MICROSCOPES & STAINS
REGULAR EFFICIENT QUALITY ASSURANCE
9
NUMBER OF CENTRES
8
7
6
5
4
3
2
1
0
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22
% POSITIVE FOLLOW-UP SPUTUM SMEARS
36
How to Use These Indicators?
•
•
•
Internal monitoring, charting
• problem: fluctuations++
• --> only larger units & selected indicators ?
During supervision visits
• can be used by TB supervisors as well
• one value, i.e. full quarter or year
• problem: time constraint in big units
• selected indicators only, i.e. low positives
• scan rather than count
Calculate from lab reports
• ideal: analysis by computer
• problem: few NTPs have lab reports!
37
Key Messages
• Problem-oriented supervision focuses on
solutions or strategies for managing particular
problems that were identified based on earlier
findings
• To ensure high quality, besides observations
also analysis of laboratory indicators, routine
performance reports and data obtained from
other EQA activities, especially blinded
rechecking, should be used.
38
Key Messages (cont.)
• It is recommended to develop and follow
algorithms when investigating errors,
including rechecking errors, during on-site
supervision
• When developing indicators, NTP
managers and NRL staff should properly
develop relevant recording and reporting
forms for data collection
39
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