Lecture № 2. The Department of Tuberculosis. KSMA. Fydorova S.V. Detection of TB cases. Lecture № 2. The Department of Tuberculosis. KSMA. Fydorova S.V.

Tuberculosis laboratory services is an essential component of the DOTS strategy and National Tuberculosis Programm. 2

Objectives and targets To cure 85% of newly detected cases of sputum-smear positive TB. To detect 70% of all smear-positive TB cases, the main sources of TB infection. 3

Methods of TB detection: X-ray-methods (fluorography) sputum microscopy tuberculin skin test hystological tests 4

Active methods of TB detection: Active examination of population (or groups of high risk) - by preventive fluorography or tuberculin skin test. 5

Passtive methods of TB detection: Passive examination of persons are suspected on pulmonary TB by sputum microscopy. 6

Direct sputum microscopy is relatively quick, simple, cheep, informative (detection of AFB provides the diagnosis of TB), is also used to monitor treatment progress and control program outcome. 7

The number from 5000 to 10000 of AFB per one millilitre of sputum is requared for direct microscopy to be positive. So patients who has positive smears eliminate the greatest number of AFB, are the most infectious (the most dangerous sources of infection). 8

Fluoragraphy absorbs all finances, doesn’t keep any finances for other targets, can detect 0,4 - 0,6 TB cases per 1000 examinated people, can’t detect any clinical forms (miliary TB, tuberculous meningitis etc), there are not any absolutely typical X-ray signs of TB, 9

Fluoragraphy is expensive, high qualification and special conditions are requared, patients don’t display initiative and stay passive. 10

Specifity of methods: Microscopy X-ray 11

Confirmation of diagnosis: Microscopy X-ray 12

Main steps during TB cases definition: Every person has cough, chest pain, weight loss, night sweats and other suspected symptoms must display initiatiative and come to the health facility. The health care worker must to suspect TB direct microscopy of 3 sputum samples consultation of specialist or antituberculous treatment. 13

Clinical symptoms are suspected on TB: cough for 3 weeks and more, chest pain, breathlessness, haemophthysis, weight loss, night sweats, fever, weakness. 14

Quality of sputum microscopy depends on: qualification of laboratory staff, laboratory equipment and materials, sputum collection procedure. 15

Sputum slides: 16

Quality of sputum collection procedure depends on two main problems: correct sputum collection procedure, the safe keeping and transport of pathological specimens for the receiving of reliable information, protection of health care workers and laboratory staff against contamination. 17

Quality of sputum collection procedure: qualificated medical staff, special place for sputum collection, special conteiner for sputum collection. 18

A good sputum specimen consists of mucoid or mucopurulent material from the bronchial tree, with minimum amounts of oral or nasal material, ideally, a sputum specimen should have a volume of 3 - 5 ml, collecting a good specimen reguares that the patient be given clear instructions. 19

Special place for sputum collection: When the patient produce a sputum specimen, aerosols containing tubercle bacilli may be formed.So patients should produce specimens outside in the open air away from other people or in the separated room with a large window and without any furniture. 20

Special place for sputum collection: Window must be opened, but the door must be closed during the sputum collection procedure. Health care worker is responsible for sputum collection must accompany the patient, give him clear instructions, control the process of sputum collection and transport the specimens of sputum to the laboratory. 21

Sputum collection procedure: explain to the patient the reason for sputum collection, instruct the patient to rinse his/her mouth with water before producing the specimen, this will help to remove food and any containing bacteria in the mouth, ask the patient to stay near the open window, 22

Sputum collection procedure: ask the patient to take to deep breaths, holding the breath for a few seconds after each inhalation, and than exhaling slowly. Ask him/her to breath in a third time and than forcefully blow in the air out. Ask him/her to breath in again and than cough. The patient should produce a specimen from deep in the lungs, 23

Sputum collection procedure: ask the patient to hold the sputum container close to the lips and to spit gently after a productive cough, ask the patient to close the container, during the sputum collection procedure the health care worker must stay behind the patient (but the wind must blow to the patient’s back) or near the door (but it must be closed), 24

Sputum collection procedure: check that the container is securely closed, and clearly label is on the container’s wall (not on the lid), wash hands with soup and water, give the patient a new sputum container and make sure that he/she understands that the second specimen must be produced next morning as soon as the patient wakes up, 25

Sputum collection procedure: demonstrate the patient how the container must be securely closed, instruct the patient bring the second specimen back to the helth center next day, after the patient has brought the second specimen back to the helth center, the third specimen must be collected under the health care worker supervision. 26

Sputum container must be: wide-mouthed (at least 35 mm in diameter), volume capacity of 50 ml, made of translucent material in order to observe specimen volume and quality without opening the container, 27

Sputum container must be: screw-capped to obtain an airtight seal and to reduce the risk of leakage during transport, easily-labelled walls that will allow the identification. 28

Dates of three sputum specimens collection: the first sputum specimen - must be taken during the first visit of the patient to the health center under the health care worker supervision after the patient has complained symptoms are suspected on TB, the second sputum specimen - must be taken next morning as soon as the patient wakes up, 29

Dates of three sputum specimens collection: the third sputum specimen - must be taken the next day too under the health care worker supervision after the patient has brought the second sputum specimen to the health center. 30

The number of sputum specimens. Why three specimens? Probability of AFB-detection: 1 specimen - 20%, 2 specimens - 30%, 3 specimens - 32%, 4 specimens - 33%, 5 specimens - 35%, and than the probability of AFB-detection increases in the more minimal degree. 31

Why three specimens? 32

Effectiveness of TB cases detection in primary health care (PHC): the number of infectious cases common number of examined patients x 100% 33

The main reasons of decreasing of effectiveness of TB cases detection (less than 5%) : all patients (without suspected symptoms) are examined by sputum microscopy, medical staff doesn’t control the sputum collection procedure, poor quality of laboratory material, poor qualification of laboratory staff. 34

The main reasons of increasing of effectiveness of TB cases detection (more than 10%) : only patients with diagnouse of TB is proved by other methods (fluorography) take examination by sputum microscopy contact persons, chronic patients, patients with control of chemotherapy are acounted. 35

The number of cases for different targets: Monitoring of treatment cases: 2 specimens after the intensive phase of treatment (2-3 monthes), after the 3-rd - 4-th month when sputum specimen stays positive, in the 5-th month, at the end of treatment (after the 6-th-8-th month). Diagnostic target: 3 specimens before the starting of treatment 36

Assessment of sputum microscopy results (diagnouse «tuberculosis» is proved) : when two specimens are positive, the third specimen isn’t necessary, when only one specimen is positive, the third specimen is necessary, when only one specimen is positive, but two specimens are negative, the patient must have typical clinic or roentgenological symptoms, 37

Assessment of sputum microscopy results (diagnouse «tuberculosis» is proved) : when 3 specimens are negative, chest X-ray and a broad range antibacterial therapy are necessary, when after the course of a broad range antibacterial therapy has been finished X-ray symptoms are kept, the repeated sputum microscopy and consultation of specialist are necessary. 38

Diagnostic procedure for suspected pulmonary TB: All Pulmonary TB Suspects + + + + + - - - - Sputum AFB Microscopy + - - Non-anti TB antibiotics no improvment improved X-ray and medical officer judgement Repeated AFB + - - + + - - - - Yes TB No TB 39 X-ray and medical officer’s judgement

Imperfection of sputum microscopy: dangure of contamination during the sputum collection procedure, low sensibility (50000 - 500000 of microorganisms per 1 ml of sputum; 5000 per 1 ml - WHO), identification of the Mycobacterium type and drug resistance by microscopy is impossible, 40

Imperfection of sputum microscopy: is not informative in childreh, patients with extra-pulmonary TB, TB patients coinfected with HIV-infection. 41

Sputum microscopy is the most priority method on the detection of TB cases. 42

Thank you for attention! 43