MICROSCOPY SMEAR EXAMINATION

RECORDING & REPORTING

Content OverviewContent Overview

•Required materials •Reading the smear•Appearance of AFB•Malaysia grading scale•WHO/IUATLD grading scale•Cleaning of objectives•Storage of smears

Systematic Examination Systematic Examination of Smearsof Smears

2 cm

3 cm

Overview of MicroscopyOverview of Microscopy• Place smear facing upwards onto stage • Focus using 10x objective• Apply immersion oil and focus 100x

objective• Examine at least 300 fields• Quantitate AFB• Record and report results• Store all smears

Stained Smear - 1Stained Smear - 1Stained Smear - 1Stained Smear - 1

AFB in Single AFB in Single ArrangementArrangement

AFB - in Various AFB - in Various ArrangementsArrangements

AFB - in Various AFB - in Various ArrangementsArrangements

Excessive Heat Fixing of Excessive Heat Fixing of SmearSmear

Glass Slide Scratch and Glass Slide Scratch and AFBAFB

What is the importance of What is the importance of Smear grading ?Smear grading ?

-To know the disease status-Quality Control

Application of OilApplication of Oil

3 cm = 100 visual field

OBSERVATION OF STAINED SMEAROBSERVATION OF STAINED SMEAR(old Malaysian standard)(old Malaysian standard)

•Examine the smear under x100 objective with the 10 eye piece lens

•Read at least 300 visual fields to give a report a negative

Recording and reportingRecording and reporting- maximum 50 bacilli is counted- maximum 50 bacilli is counted

Old Malaysian Standard

If 50 or more bacilli found in the first line

> 50 /L

11 to 49 bacilli seen at the end of first line Write the actual no. of AFB seen

35/L, or 11/L

If 50 bacilli seen in any part of the slides

50/ >L

Number of bacilli seen after 3 lines examined Write the actual no. of AFB seen

3/3L or 49 /3L

No AFB seen 0/3L

3 cm = 150 visual field

•Examine the smear under x100 objective with the 10 eye piece lens

•Read at least 300 visual fields to give a report a negative

OBSERVATIONOBSERVATION OF STAINED SMEAR OF STAINED SMEAR-International Standard--International Standard-

Number of AFB

Number of fields* examined

What to report

No AFB in 300 fields

300 fieldsNo Acid Fast Bacilli seen

1–9 AFB in 100 fields 100 fields

Record exact figure (1 to 9 AFB per 100 fields)

10– 99 AFB in 100 fields 100 fields

1 +

1– 10 AFB in each field 50 fields

2 +

More than 10 AFB in each

field20 fields

3 +

* Oil immersion fields

Recording and Recording and ReportingReporting

Interpretation of Smears

Smear Contains Smear Contains No AFB in 300 No AFB in 300 FieldsFields will be will be graded asgraded as No AFB Seen

00 -- No AFB seen in 300 visual No AFB seen in 300 visual fieldsfields

1VF 2VF 3VF 4VF................................ 148VF 149VF 150VF

1-9 AFB seen 1-9 AFB seen in100 VF in100 VF will will be graded asbe graded as

Scanty

Scanty - 1-9 AFB seen in 100 VF(Write the actual number of AFB seen, e.g. 1/100VF,

3/100VF…9/100VF)

Scanty - 1-9 AFB seen in 100 VF(Write the actual number of AFB seen, e.g. 1/100VF,

3/100VF…9/100VF)

7/100VF

A smear with A smear with 10 to 99 bacilli 10 to 99 bacilli in 100 fields in 100 fields will be graded will be graded as as 1+

1+

1+1+ - 10-99 AFB seen in 100 VF- 10-99 AFB seen in 100 VF

1+

1+1+ - 10-99 AFB seen in 100 VF- 10-99 AFB seen in 100 VF

A smear with A smear with 1 to 9 bacilli in 1 to 9 bacilli in at least 50 at least 50 fields will be fields will be graded asgraded as 2+

2+

2+2+ -- 1-10 AFB/OIF in at least 50 1-10 AFB/OIF in at least 50 VFVF

1VF=3 2VF=1 3VF=2................ 49VF=3 50VF=4

A smear with A smear with more than 10 more than 10 AFB/OIF in at AFB/OIF in at least 20 fields least 20 fields will be graded will be graded asas 3+

3+3+ - - More than 10 AFB/OIF in at least 20 More than 10 AFB/OIF in at least 20 VFVF

3+

Recording ResultsRecording Results

Cleaning the Cleaning the ObjectivesObjectives

How to store the slides?How to store the slides?

Remove Oil from SmearsRemove Oil from Smears

Storage of SmearsStorage of Smears

What will happen when the What will happen when the smear results are reported smear results are reported

incorrectly ?incorrectly ?

These variations can be minimized by;

MAIN CAUSES OF FALSE READINGS IN MAIN CAUSES OF FALSE READINGS IN SMEAR PREPARATIONSMEAR PREPARATION

Check point Causes False Positive

F(+)

False Negative

F(-)

Size Too bigToo small

**

Evenness UnevenSloughed-off

**

Thickness Too thickToo thin

**

Cleanliness DirtArtifact

**

*

Sputum quality

Saliva *

Staining OverheatingInsufficient heatingUnder decolourization

*

*

***

False Negatives and False Negatives and ConsequencesConsequences

False Positives and False Positives and ConsequencesConsequences

Grade the Following Grade the Following Smears:Smears:

EXERCISE

SMEAR 1

6/100VF6/100VF

Grading-1Grading-1Grading-1Grading-1

Smear-2Smear-2Smear-2Smear-2

Grading-2Grading-2Grading-2Grading-2

1+1+

Smear- 3Smear- 3Smear- 3Smear- 3

GRADING-3GRADING-3

2+

Smear-4Smear-4 Smear-4Smear-4

GRADING-4GRADING-4GRADING-4GRADING-4

8/100VF8/100VF

Smear-5Smear-5Smear-5Smear-5

Grading-5Grading-5

3+3+

Smear-6Smear-6Smear-6Smear-6

Grading-6Grading-6Grading-6Grading-6

2+2+

Smear-7Smear-7Smear-7Smear-7

Grading-7Grading-7Grading-7Grading-7

1+1+

Smear-8Smear-8Smear-8Smear-8

Grading-8Grading-8Grading-8Grading-8

1+1+