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1 Module 5 Laboratory Diagnostics, Specimen Collection, and Biosafety Issues.

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Presentation on theme: "1 Module 5 Laboratory Diagnostics, Specimen Collection, and Biosafety Issues."— Presentation transcript:

1 1 Module 5 Laboratory Diagnostics, Specimen Collection, and Biosafety Issues

2 2 Learning Objectives Prepare and maintain collection kits Collect and transport specimens safely and correctly Manage laboratory specimens safely Interpret laboratory data

3 3 Session Overview Specimen collection Specimen storage, handling, shipping Disposing infectious waste in the field Safety precautions in the laboratory Working with reference laboratories Managing laboratory data

4 4 The Specimen Collection Kit

5 5 Specimen Collection Kit Viral transport medium (VTM) Preparing the specimen collection kit Managing the specimen collection kit

6 6 What is Viral Transport Medium? Used in the collection of samples for viral isolation and testing Prevents specimen from drying out Prevents bacteria and fungi growth

7 7 How to choose VTM Can be made in a lab or purchased Different types of VTM: –For collection of animal specimens –For viral isolation –For molecular testing (Do not use phosphate-based media) If VTM is not available, 100% ethanol can be used for molecular testing

8 8 Storing VTM Sterile collection vials containing 2-3 ml of VTM Vials can be stored in a freezer at -20 ºC until use Vials can be stored for short periods of time at ºC

9 9 Managing Media Stock Keep records of when the VTM was made Do not use vials if the liquid becomes cloudy

10 10 Specimen Collection Kit Collection vials with VTM Polyester fiber-tipped applicators Sterile saline (0,85% NaCl) Sputum or mucus trap Tongue depressors Specimen collection cups or Petri dishes Transfer pipettes Secondary container Ice packs Items for blood collection Personal protective equipment Field collection forms A pen or marker for labeling samples

11 11 Sputum Trap

12 12 Polyester Fiber-Tipped Applicator Should be drayon, rayon, or polyester- fiber swabs Do not use calcium alginated or cotton swabs nor ones with wooden sticks; they inhibit PCR

13 13 Tongue Depressors

14 14 15 ml Conical Centrifuge Tubes

15 15 Specimen Collection Cups and Petri Dishes collection cups petri dishes

16 16 Transfer Pipettes

17 17 Phlebotomy Supplies Tourniquet Disposable needles Vacuum tubes with EDTA Plastic needle holder Alcohol and iodine swabs Gauze Band-aids Biohazard sharps container

18 18 Personal Protective Equipment Gloves Mask Gown Eye protection

19 19 How to Manage Kits Store specimen collection kits in a dry, cool place Store specimen collection kit where it will be accessible after hours and on weekends

20 20 How to Safely And Correctly Collect Samples

21 21 Clinical Specimen Collection Responsibility Usually a hospital staff function May be a rapid responder function if hospital staff are unavailable Designate at least one member of the team trained to collect specimens

22 22 Clinical Specimen Sources Be prepared to collect specimens before you leave for the field Suspected cases –Symptoms consistent with influenza Contacts –Including people living or working with suspected cases

23 23 What to Collect Preferred specimens Nasal swabs Throat swabs When possible: Nasopharyngeal specimens Other specimens Posterior pharyngeal swabs Nasal washes Acute and convalescent serum Collect the sample on several different days

24 24 What to Collect From an Ambulatory patient Nasal swab and Throat swab Can be collected into the same VTM From an Intubated patient Lower respiratory aspirate

25 25 When to Collect Respiratory Specimens As soon as possible after symptoms begin Before antiviral medications are administered Even if symptoms began more than one week ago Collect multiple specimens on multiple days

26 26 Respiratory Specimens Nasopharyngeal aspirate or swabs Posterior pharyngeal swabs Nasal swabs or nasal wash Nasopharyngeal aspirate and nasopharyngeal swabs have greatest sensitivity in detecting influenza virus

27 27 Serological Samples Paired serum samples are most useful Acute sample Within 7 days after symptom onset Convalescent sample More than 21 days after symptom onset

28 28 Alternative Diagnostic Testing If avian influenza is not the cause of the illness, consider the following alternative diagnostic testing: –Culturing for other respiratory viruses –SARS testing –Rapid influenza test –PPD for tuberculosis

29 29 Personal Protective Equipment Masks (N-95 or N/P/R-100) Gloves Protective eye ware (goggles) Hair covers Boot or shoe covers Protective clothing (gown or apron)

30 30 How to Collect Specimens

31 31 Field Data Collection Form Patient name Unique identification number Patient demographic information Patient’s health status

32 32

33 33 Specimen Tracking System Maintain a database to track: Identification number Subject information Specimen collection date Specimen collection location Diagnostic test results

34 34 Nasopharyngeal Swab 1.Insert dry swab into nostril and back to nasopharynx 2.Leave in place for a few seconds 3.Slowly remove swab while slightly rotating it

35 35 Nasopharyngeal Swab continued 4.Use a different swab for the other nostril 5.Put tip of swab into vial containing VTM, breaking applicator’s stick

36 36 Nasopharyngeal Swab Demonstration

37 37 Posterior Pharyngeal Swab Ask the subject to open his or her mouth Depress the tongue Swab the posterior pharynx Avoid the tonsils

38 38 Posterior Pharyngeal Swab Demonstration

39 39 Nasopharyngeal Aspirate Collection Process 1.Attach mucus trap to vacuum source 2.Place catheter into nostril parallel to palate 3.Apply vacuum 4.Slowly remove catheter while slightly rotating it 5.Repeat with other nostril using the same catheter 6.After collection, flush catheter with 3 ml VTM and return VTM to a plastic vial

40 40 Nasopharyngeal Aspirate Demonstration

41 41 How to Collect Blood 1.Put tourniquet on subject Photos: CDC/ Jim Gathany

42 42 How to Collect Blood 2.Clean area with iodine and alcohol

43 43 How to Collect Blood 3.Attach assemble needle, needle holder, and collection tube

44 44 How to Collect Blood 4.Insert needle into vein Collect at least 2 ml blood

45 45 How to Collect Blood 5.Remove needle and apply pressure

46 46 How to Collect Blood 6.Dispose of needle in biohazard sharps container Do not reuse a needle

47 47 Patient Care After blood draw, apply light pressure After removing gauze, place a sterile Band-Aid

48 48 How to Label Samples Use pre-printed barcode labels: –On the specimen container –On the field data collection form –On the log book Label each specimen with: –Subject’s name –Subject’s unique identification number

49 49 Personal Protective Equipment Masks (N-95 or N/P/R-100) Gloves Protective eye ware (goggles) Hair covers Boot or shoe covers Protective clothing (gown or apron)

50 50 Antecubital Venipuncture (Blood Sample) Demonstration

51 51 Specimen Storage, Handling, and Transportation

52 52 How to Store Specimens For specimens in VTM: Transport to laboratory as soon as possible Store specimens at 4 °C before and during transportation within 48 hours Store specimens at -70 °C beyond 48 hours Do not store in standard freezer – keep on ice or in refrigerator Avoid freeze-thaw cycles –Better to keep on ice for a week than to have repeat freeze and thaw

53 53 How to Store Specimens For sera: Store specimen at 4 °C For both VTM specimens and sera, avoid repeated freeze-thaw cycles

54 54 Handling Infectious Materials in the Field Always wear personal protective equipment Be careful with sharp objects Treat all clinical samples as potentially infected with avian influenza

55 55 Packing Specimens for Transportation Use three packaging layers First layer should be water tight Use absorbent material in all layers No more than 500 mL should be in the specimen container

56 56 Transporting Specimens from Field to Lab

57 57 Keep specimens at 4 ºC –Fill a cooler with ice packs or coolant packs –Double-bag specimens if you use dry ice Include an itemized list of specimens with identification numbers and laboratory instructions Packing Specimens for Transportation

58 58 Transporting Specimens Refer to WHO guidelines for the safe transport of infectious substances and diagnostic specimens Follow local regulations on the transportation of infectious material Coordinate with the laboratory

59 59 Packaging a Specimen for Shipment Demonstration

60 60 Waste Disposal in the Field

61 61 Items Requiring Disposal Infectious blood, body fluids, leftover biological samples Disposable needles and syringes * Disposable or non- reusable protective clothing * Disposable or non- reusable gloves Used laboratory supplies * Used disinfectants * Incineration recommended

62 62 Building an Incinerator 1.Cut out one end of a 220 liter drum 2.Cut out 3 half-moon openings 3.Cut 4 side holes and insert metal rods to form an X 4.Cut away half of other end of drum to form lid 5.Insert first end cut as a waste platform

63 63 How to Burn Waste in An Incinerator 1.Place waste on platform inside of the drum 2.Soak waste in one liter of fuel 3.Light the fire carefully 4.Watch the fire and frequently mix the waste with the metal bars to be sure all of the waste is burned 5.When the fire has gone out, empty the ashes into a pit Note: You must replace the incinerator if large holes burn through the sides.

64 64 Disposal Using a Pit Can be used for disposal of: –Liquids, if no isolation latrine or toilet is available –All other flammable items such as clothing Building a Pit: –Locate pit far from foot traffic flow –Dig 2 meters deep, wide enough to hold all contaminated waste material

65 65 How to Burn Waste in a Pit 1.Place disinfected waste in the pit 2.Pour fuel over waste 3.Carefully start fire 4.Observe burning process 5.Repeat fire if waste remains after burning 6.Cover ashes with soil 7.Bury a nearly full pit with ½ meter of soil 8.Dig a new pit for more waste

66 66 Disposal Safety Precautions Use safe handling practices for infectious material Locate disposal site on health facility grounds, away from traffic flow and public view Maintain disposal site security by roping off, posting signs, and stationing a guard Do not leave unburned waste in an incinerator or pit

67 67 Laboratory Safety

68 68 Storing Specimens in The Lab Label specimens as potentially infectious Store specimens in a secondary container Store specimens in freezer at -70 °C –Use a temperature alarm, generator, and back-up –If a -70 °C freezer is not available, store at 4 °C until sample can be transported to another lab

69 69 Laboratory-Associated Risks An infectious sample is aerosolized A worker is exposed to a needle stick

70 70 Safe Laboratory Specimen Handling Follow standard precautions Follow Biosafety Level 2 procedures Minimize formation of aerosols and droplets Avoid using needles

71 71 Laboratory Safety Basics Biosafety Levels: BSL 1: Wash hands, no food or drink, door that can be closed BSL 2: Good microbiological techniques, protective clothing, biological safety cabinet BSL 3: BSL 2 plus directional air flow, special clothing, and controlled access BSL 4: BSL 3 plus isolated building, one-piece protective suits with respirators

72 72 Laboratory Safety Basics BSL 3 work practices: Perform procedures that may generate aerosols or droplets in a biological safety cabinet Wear gloves, gowns, eye protection, and a mask Decontaminate work surfaces after use

73 73 Guidelines for Potential Avian Influenza Specimens Use BSL 2 laboratory with BSL 3 practices for: –Diluting specimens –Nucleic acid extractions –Diagnostic testing that does not involve culturing Use BSL 3 laboratory with BSL 3 practices for: –Culturing avian influenza virus

74 74 Managing Contamination or Accidents Contaminated work surface: Use 5% bleach solution for at least 5 minutes Make bleach solution fresh daily Exposed laboratory worker: Remove infected clothing Wash any exposed areas Give post-exposure prophylaxis according to the established emergency procedure

75 75 Reference Laboratories

76 76 Reference Lab and Transporter The referral laboratory and the recommended transporters vary by country More specific information will be provided here

77 77 In-country Referral Laboratories Provincial / District level laboratories, if any National level laboratories, if any

78 78 WHO H5N1 Laboratory Network All viruses from human cases of avian influenza should be shipped to a WHO reference laboratory for: Vaccine development Antiviral susceptibility testing Other activities of public health significance

79 79 Managing and Analyzing Laboratory Data

80 80 Data Management Rules Double check data entry accuracy Include unique identification numbers Keep subject names confidential Track testing dates and results Back up the database

81 81 Computer Software Epi-info (CDC) –Free, at Microsoft Excel and Access Oracle MySQL Filemaker Pro

82 82 Data Analysis Measures Prevalence The number of cases divided by the size of the population Sensitivity The number of cases identified by the test divided by the number of true positives which were identified by the gold standard technique Specificity The number of non-cases identified by the test divided by the number of true negatives that were identified by the gold standard technique

83 83 How to Present Results Report: Time and place of the outbreak Prevalence of infection Clinical information about cases Epidemic curve Share results with local health officials and the WHO Global Influenza Program

84 84 Summary Maintain adequately stocked specimen collection kits and store them properly when they are not in use. Nasal swabs and throat swabs are the easiest specimens to collect; Nasopharyngeal aspirate and nasopharyngeal swabs have greatest sensitivity in detecting influenza virus. Collect multiple specimens (respiratory and blood) on multiple days.

85 85 Summary Proper specimen storage, handling, and shipping is vital to a successful laboratory test. Keep track of information on the specimens collected in a database or logbook. When handling infectious materials in the laboratory or in the field, take safety precautions. Properly dispose of any infectious material.

86 86 Summary Most countries will be able to perform some basic influenza identification tests on a clinical specimen, but more specific testing may need to be done at a higher level national or regional laboratory. When you report on the progress of an outbreak investigation, share investigation results with local health officials and the WHO Global Influenza Program.

87 87 Laboratory Practice Exercises

88 88 Glossary Centrifuge A machine that uses high-speed rotation to separate materials with different densities. Culture The growing of microorganisms in a nutrient-rich medium. Nucleic acid A component genetic material such as DNA or RNA found in all cells in humans, animals, bacteria, and viruses. Every species and organism has a unique pattern.

89 89 Glossary Pipette A glass or plastic tube used to measure or transfer small amounts of liquid. Saline A liquid solution made of salt and water. Viral Transport Medium (VTM) The preservative liquid in which specimens are stored until they are tested.

90 90 References and Resources Recommended laboratory tests to identify avian influenza A virus in specimens from humans. World Health Organization, June, lines/avian_labtests2.pdf lines/avian_labtests2.pdf WHO guidelines for the collection of human specimens for laboratory diagnosis of avian influenza infection, 12 January lines/humanspecimens/en/index.html lines/humanspecimens/en/index.html Infection control for viral haemorrhagic fevers in the African health care setting. WHO/EMC/ESR/98.2 Section 6: Dispose of Waste Safely WHO_EMC_ESR_98_2_EN/en/index.html WHO_EMC_ESR_98_2_EN/en/index.html


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