(M) Lesson 9: Direct Sputum Smear Microscopy Flashcards
Test to see whether there are TB bacilli present in the phlegm
Direct Sputum Smear Microscopy (DSSM)
- To test this, the MedTech will smear phlegm on a thin glass slide with a special stain and look for TB bacilli on the slide under the microscope
- This usually takes 1 day to get the results
DSSM
- Main tool for the diagnosis of Pulmonary TB
- It provides a definitive diagnosis of active TB
- Active TB means it spreads/multiplies inside the body
DSSM
- Simple and economical procedure
- Usually easy to set up (All you need is a skilled microscopist, compound microscope and materials for sputum smear)
DSSM
- Is an infectious disease caused by Mycobacterium tuberculosis
- It is an illness in which the bacteria are multiplying, attacking a part of the body (usually the lungs)
TB Disease
- TB disease that occurs in lungs
- If a patient is infected, it produces cough that lasts 3 weeks or longer
Pulmonary TB
- A condition which TB bacteria are alive but inactive in the body
- Patient with latent TB do not have symptoms and cannot spread TB to other people
- Usually have a positive TB skin test
Latent TB Infection
- TB disease in any part of the body other than the lungs
- Example: Kidney, Spine, Brain, or Lymph Nodes
Extra-Pulmonary TB
- Liquid that is injected under the skin during TB skin test to diagnose latent TB infection.
- PPD stands for Purified Protein Derivative
Tuberculin or PPD
- Directly observed therapy
- You will meet the health worker everyday for several weeks in the health center
DOT
- Good Ventilation
- Table/bench to prepare smears
- A sink or plastic basin to stain smears
- Table/bench for Microscope and paper works
- Non-slip flooring
- Area for receiving of specimens
Basic requirements for TB Microscopy Laboratory
Zone Divisions in TB Laboratory
For microscopy, record keeping and storage areas
Clean Zone
Zone Divisions in TB Laboratory
Specimen receiving, and smear preparation and staining are performed
Dirty Zone
- Moving in a single direction
- You may open your windows or fan for proper ventilation, but the airflow should still be unidirectional
- Clean to dirty areas
Unidirectional airflow
Potential Hazards
- Coughing is a good mechanism for producing aerosols through droplet nuclei.
- Provide a designated area for sputum collection.
Sneezing or Coughing by TB patients
T or F: Patients are allowed to collect sputum in the bathroom.
F (not allowed)
Potential Hazards
- It still produces aerosol
- Flaming a wire loop with adherent sputum
- Heat fixing the smear while still wet
Potential Hazards
- One of the most common potential hazard (in the whole laboratory)
- Wear PPEs in handling specimen
Poor handling of specimen
Potential Hazards
- Ensure proper storage of reagent and use small containers
Fire from flammable reagent
Familiarize yourself with the safety practices in TB laboratory.
- Assume ALL specimens are potentially infectious
- Never smoke, eat or drink in the laboratory
- Wash hands with soap and water at least before and after performing any procedure
- Keep the windows open to establish airflow in working areas
- Quantities of flammable reagents should be safe, cool and in well-ventilated storage place
- Formation of aerosols must be avoided as strictly as possible
T or F: We should reject broken or leaking containers.
Teh, edi T
____ is a potential hazard to the laboratory personnel
Leaking containers
Once collected, allow the sputum specimen to stand undisturbed for ____ before opening to settle any aerosol.
at least 20 minutes
Open sputum containers with care and away from the face to prevent ____.
Splashes
How do we remove residual sputum?
Swirl the wire loop in the sand or beads containing 70-90% alcohol before sterilizing in a flame to prevent aerosol.
N95 vs. Surgical Masks
- Do not filter out infectious droplet nuclei
- Does not significantly reduce the risk of infection by aerosol inhalation
Surgical Masks
- Effective respiratory protection is expensive and must be fitted correctly to be functional
- Offer better protection against respiratory aerosols
- Designed to filter airborne particles compared to surgical masks that filters larger particles and block splashes
N95
T or F: Do not reuse gloves and never wear gloves outside the laboratory.
T
T or F: Remove gloves before operating equipment to avoid contamination
T
- Always wear gloves in performing laboratory procedures
- Change ASAP if they are dirty or torn
T
How should laboratory coats be worn?
- Fully buttoned with sleeves down
- Should cover the entire upper body because it will give you extra protection
How do we handle accidental contamination on the bench or the floor?
- Place a paper towel or cloth over the spill area and apply disinfectant solution such as 5% hypochlorite/phenol
- Stand for 15-20 minutes
- Clean the contaminated material and put it inside the waste container
- **For final wash: ** clean with 70% alcohol
- Wash hands thoroughly
The success rate of obtaining a positive smear will also depend on the?
Quality of specimen
- Should contain mucoid or mucopurulent material
- Should be obtained from the lower respiratory tract rather than the sample consisting saliva
Good quality sputum
Contains pus, composed of white blood cells, cellular debris, dead tissue, serous fluid, and viscous liquid (mucus)
Purulent sputum
- Typically yellow or green
- Seen in cases of bronchitis or acute upper respiratory tract infection (common cold, laryngitis)
Purulent sputum
- Often described as off-white, yellow, green, opaque and sometimes red coloration
- Idicates large amount of white blood cells
Mucopurulent sputum
A good quality sputum should contain?
- Mucoid
- Mucopurulent
- Bloodstained material (tinge of blood)
- Thick consistency
Indicators of saliva?
Mostly composed of bubbles that are thin and watery
Ideal Specimen Container
Familiarize.
- Volume capacity of 50 mL
- Made of transparent material
- Wide-mouthed (at least 35 mm in diameter)
- Screw-capped
- Leak-proof and unbreakable
- Easily labeled walls
- Single-use combustible material
Labels to be put on the container?
- Patient name
- Date and Order of Collection
- Laboratory Serial Number
These are pulmonary specimens.
- Sputum (Expectrorate and Induced)
- Laryngeal Swab
- Bronchial Secretions
- Pleural Effusions
- Gastric Lavage/Aspirate
Specimen of choice for detection of Tb
Sputum
Produced by inhalation of warm aerosol of strike 5-10% sodium chloride in water produced by nebulizer
Induced Sputum
- Indicated for children who produce almost no sputum
- Rarely used for adults
Gastric Lavage/Aspirate
Extra-pulmonary Specimen
Collected Aseptically
* Body Fluids
Not Collected Aseptically
* Urine
* Semen and Prostate secretions
* Stool samples
How many sputum specimens are recommended for the laboratory diagnosis of TB?
Two
Identify the type of sputum collection.
- Specimen 1: Specimen is collected anytime of the day
- Specimen 2: Early morning collection
Spot Early Morning Collection
Identify the type of sputum collection.
- Two consecutive sputum specimen, collected on the same day at least 1 hour apart
Spot-Spot Collection (Frontloading)
Hi, please study how to prepare a smear as well as the staining methods <3
Nasa transes ni Anne mwa.
Good luck !!
How to examine a smear?
Scan the smear by moving across the smear in horizontal direction (end to end).
Read ____ before reporting a negative result. If no AFB is seen in one length, examine another horizontal length of the slide.
at least 300 visual fields
Usually ____ may be read if the slide is positive for AFB.
100 fields
National Reporting Scale for AFB
No AFB seen in 300 visual fields
0
National Reporting Scale for AFB
1-9 AFB seen in 100 visual fields (write the actual number of AFB seen)
Example: +1, +2, +3, +4
+n
National Reporting Scale for AFB
10-99 AFB seen in 100 visual fields
1+
National Reporting Scale for AFB
1-10 AFB/OIF in at least 50 visual fields
2+
National Reporting Scale for AFB
More than 10 AFB/OIF in at least 20 visual fields
3+
Hello me ulit, please study and read the prevention of false-positive and false-negative sputum results hehe.
Go bff!!
Consequences of False Positivity
Unnecessary treatment (wastage of drugs)
Consequences of False Negativity?
- Patient remains untreated, resulting in suffering, spread of TB and death
- Intensive phase treatment may not be extended, leading to inadequate treatment
