Health Care Worker Training on Roll Out New TB Diagnostic Test. Prepared by: City Health (J Caldwell) & NHLS (M Bosman & I Noordien)

Transcription

1 Health Care Worker Training on Roll Out New TB Diagnostic Test Prepared by: City Health (J Caldwell) & NHLS (M Bosman & I Noordien)

2 Overview Specimen Collection Investigations to request Sorting & registering specimens New Diagnostics o GeneXpert NHLS Reports o Fax Lists o Hard Copies o o Telephonic Ordering Diagnostic tests used by NHLS o Microscopy o Culture o Differential o DST o Hain (LPA)

3 Why are we using GeneXpert now? WHO Recommendation (2010) and NSP WHO Strong Recommendation: The new automated DNA test for TB should be used as the initial diagnostic test in individuals suspected of MDR-TB or HIV/TB (i.e. Most TB suspects in SA) Pillars of SA National Strategic Plan: ( draft) Universal testing for HIV and screening for TB the primary objectives being to ensure that all citizens know their HIV and TB status, and to prevent new HIV and TB infections Health and wellness the primary objective being to ensure access to quality treatment, care and support services for those with HIV and/or TB and to develop programmes to focus on wellness Slide courtesy of Prof Wendy Stevens

4 Advantages and limitations Advantages Decreased turn around time to reduce the diagnostic delay Increased sensitivity and specificity Only detects Mycobacterium tuberculosis complex Can be used in children who can cough (induced sputum) Can be used by non-laboratory staff

5 Disadvantages Disadvantages Cannot be used for monitoring Only detects rifampicin resistance Qualitative result Copyright NHLS 2003 Slide 5

6 Specimen Collection NOTE: Quality of the result is ONLY as good as the quality of the specimen received

7 Sputum Collection Use external sputum booths (where available) to collect specimens - if no booth suggest outside building Make sure no other patients are present Always stand BEHIND the patient EXPLAIN the steps to the patient and make sure the patient understands: o Ask the patient to rinse mouth with water o Advise patient to be careful & direct sputum into container so as not to contaminate outside of container o Give the patient LABELLED container without the lid o If the patient does not cough spontaneously, ask the patient to take several deep breaths and then hold their breath o Seal sputum jar properly after specimen produced

8 Closing sputum container Check contents sputum jar Need at least 5ml sputum per jar Tighten cap of sputum jar to make sure it does not leak Place sputum jar into plastic bag obtainable from the NHLS

9 What investigations to request on TB Suspects ALL TB suspects to have 2 spot sputum specimens taken ONE hour apart Previously requested: o New: direct x2 o Retreatment: direct x2 & x1 culture and DST o HCW s, prisoners, contacts DR-TB patients: direct x2 & x1 culture and DST Now request GeneXpert

10 Extrapulmonary samples Circular H Restriction of Genexpert test requests on specimens other than Sputa and Tracheal Aspirate.pdf Copyright NHLS 2003 Slide 10

11 Sputum Request Form Complete the request forms properly Use (PreHmis) PHC patient stickers on sputum jar and on NHLS request form Fold the request form with the patients details facing outward Insert the sample into the correct sleeve of NHLS specimen bag Insert the form into the other sleeve

12 1. Name facility 2. Patient Details (patient sticker) 3. Tests requested MUST add HIV status under remarks (HIV +ve/hivve/hiv unknown) and write GeneXpert 4. Specimen collection details Copyright NHLS 2003 Slide 12

13 Preparation for dispatch sputum specimens to NHLS The TWO plastic bags must be stapled together at the top (each bag contains 1 specimen & 1 request form) Both specimens (stapled together) must be sent to NHLS together and preferably should be sent to NHLS on the same day If it cannot be sent on the same day, keep refrigerated (if no fridge available keep in a cool dark place)

14 Samples stapled together

15 NHLS Sputum Request Form KMBT pdf Copyright NHLS 2003 Slide 15

16 Sorting and Registering Specimens at NHLS On receipt of sputum samples NHLS sorts & registers each specimen received on database BEFORE dispatching to each section for testing. NOTE each specimen has its own unique registration number - each lab has own code (SGT XXXX or SWO XXXX) Leaking specimens are registered BUT discarded report sent to clinic specimen leaked, please repeat

17 Each specimen receives a unique registration number i.e. SGT Information from sputum request form used to register each specimen according to whether suspect/case & TB history i.e. new/rerx

18 TB Suspects Always 0 months New suspect = SPN0 Retreatment suspect = SPR0 Each specimen receives a unique registration number i.e. SGT Information from sputum request form used to register each specimen according to whether suspect/case & TB history i.e. new/rerx Confirmed Drug Sensitive TB Case Conversion sputum done at 7 weeks or 11 weeks New TB case conversion = SPN2 Retreatment TB case conversion = SPR2 Discharge sputum done at 5 months or 7 months New TB case discharge = SPN5 Retreatment TB case discharge = SPR5 Other Please note if no time stated New = SPUN Retreatment = SPUR If it is NOT indicated if a suspect or a case and/or new or retreatment will be registered as SPU Confirmed Drug Resistant TB Case Monthly sputum sample sent on all drug resistant TB cases (MDR and/or XDR) for smear and culture will be registered as SPMDR

19 What TB diagnostic tests are used by NHLS? Diagnostic Tests Direct (microscopy) Culture (MGIT) Drug Sensitivity Testing Line Probe Assay (Hain) New Diagnostic Tests GeneXpert

20 New Diagnostic Test

21 Why the need for new diagnostics? Need tests to confirm diagnosis in sm- TB & drug resistance much sooner to be able to start treatment sooner Direct not very sensitive Culture takes up to 5 weeks

22 MTB/RIF cartridge and GXP 4

23 GeneXpert Technology Xpert MTB/RIF Assay GX1 GX2 GX4 GX16 GeneXpert Infinity throughput/8 hr day

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26 What is GeneXpert (GXP) The GXP is a platform for the Xpert MTB/Rif cartridge-based fully automated nucleic acid amplification test for TB case detection and rifampicin resistance Designed to extract, amplify and identify targeted 6110 and rpob nucleic acid sequences Note - additional tests cannot be ordered after GXP has been done

27 Which samples get GXP? ALL TB suspects one sputum specimen will have genexpert (includes new; ReRx; MDR contacts; HCWs & prisoners) Only 1 GXP test will be done per patient GeneXpert CANNOT be used for follow-up specimens on patients with confirmed TB on treatment need to follow Palsa Plus i.e. & send either smear or culture for conversion & discharge monitoring

28 What are the benefits of GeneXpert? GeneXpert more sensitive To see AFBs on smear needs 10,000 bacilli per ml GeneXpert only needs 150 bacilli per ml Copyright NHLS 2003 Slide 28

29 What are the benefits of GeneXpert? GXP has specificity of 99.2% Detects 70% sm-ve Useful in the diagnosis of TB in HIV co-infected patients Has an instrument turnaround time of 2 hours results will be back at facility within 24 hours Easy to use

30 How to interpret GeneXpert results & what to do?

31 Copyright NHLS 2003 Slide 31

32 GeneXpert +ve and Rifampicin Sensitive 2 GXP MTBCD Pos Rif S.pdf

33 GeneXpert +ve Rifampicin Sensitive On receipt of GeneXpert result Start TB treatment do NOT wait for sm result When sm result received register as either sm+ve OR sm-ve Follow-up at conversion or discharge as per Palsa Plus for sm+ve or sm-ve

34 Copyright NHLS 2003 Slide 34

35 GeneXpert Positive & Rifampicin Resistant 3 MTBCD Rif R.pdf

36 GeneXpert +ve Rifampicin Resistant On receipt GeneXpert result Recall patient for review by PHC MO MO to prescribe MDR treatment with additional INH When cul & DST received MO to review treatment & STOP INH Register patients in DR-TB register

37 Copyright NHLS 2003 Slide 37

38 Rif inconclusive.pdf

39 GeneXpert +ve Rifampicin Inconclusive On receipt GeneXpert result Start drug sensitive TB treatment do NOT wait for sm, culture & DST result When culture & DST result received as RESISTANT stop DS TB treatment & start DR TB treatment When culture & DST result received as SENSITIVE continue DS TB treatment Register as per sm & cul results Copyright NHLS 2003 Slide 39

40 Copyright NHLS 2003 Slide 40

41 GeneXpert Neg.pdf Please note the HIV status Copyright NHLS 2003 Slide 41

42 GeneXpert Negative If HIV+ve NHLS will use 2 nd specimen to do culture & DST On receipt GeneXpert result - manage HIV+ve and HIV-ve as per Palsa Plus

43 Copyright NHLS 2003 Slide 43

44 GXP unsuccesful.pdf

45 GeneXpert Unsuccessful On receipt GeneXpert result If 2 nd GeneXpert unsuccessful take 3 rd specimen for microscopy, culture & DST

46 GeneXpert Fax List NHLS will send out SEPARATE fax list to clinic with genexpert results GeneXpert results will NOT be included on general fax list

47 printer alignment.pdf Copyright NHLS 2003 Slide 47

48 Hard Copy

49 TB Suspect Register GeneXpert TB Suspect Register.xls Copyright NHLS 2003 Slide 49

50 Registration GeneXpert Results Record GeneXpert result in blue TB patient folder as well as any other results i.e. sm/cul Record GeneXpert result in TB register as well as any other results i.e. sm/cul Record as GX+ve/GX-ve

51 Blue TB Folder Pretreatment 2 months 3 months 5/7 months Culture Resistance Sm Date Sm Result Sm Date Sm Result Sm Date Sm Result Sm Date Sm Result Specimen Date Culture result 3/10/11 GX+ve Yes S DST Done R H Z E S 3/10/11 P+++ Remember follow Palsa Plus MUST have a pretreatment smear result for ALL patients tested Gx +ve ALL patients who are sm+ve pretreatment will need to have smears done at 7/11 weeks & 5/7 months ALL patients who are sm-ve pretreatment will NOT have any further sputums sent will be managed clinically for duration treatment

52 Turn Around Time ( TAT ) NTCP expects the laboratory to adhere to a 24 to 48 hour TAT for sputum microscopy TAT is calculated from the date the specimen is taken until the result is received at the clinic Smears on cultures take longer GeneXpert results will be available in 24 hours

53 Copyright NHLS 2003 Slide 53

54 NHLS Reports Copyright NHLS 2003 Slide 54

55 How does a clinic receive results? Fax lists Hard copy of results sent by post or brought to the clinic by the NHLS courier SMS printers Telephonic report Copyright NHLS 2003 Slide 55

56 GeneXpert Fax list.pdf Copyright NHLS 2003 Slide 56

57 Explanation of GXP Fax List GXTB PCR MTBCD Mycobacterium Tuberculosis Detected MTBCN Mycobacterium Tuberculosis NOT Detected GXRIF Rifampicin RIFS Susceptible RIFR RIFZ Resistant Inconclusive Common LEAK Specimen leaked in transit. Please repeat EMTY OSPEC NSMR Received Empty No specimen received No Smear requested

58 SMS result sms printout.pdf Copyright NHLS 2003 Slide 58

59 Auramine Fax Lists Copyright NHLS 2003 Slide 59

60 Explanation of Fax List Copyright NHLS 2003 Slide 60

61 Ordering stores from NHLS material order form.pdf Copyright NHLS 2003 Slide 61

62 ww.disa Before calling the lab please check: Copyright NHLS 2003 Slide 62

63 In summary.. Submit 2 samples together for each suspect GXP simultaneously detects TB and Rifampicin R or S NHLS uses 2 nd sample for further testing Test ordered now shows GeneXP TB Use ww.disa for result lookup

64 Questions????? Copyright NHLS 2003 Slide 64

65 Other Diagnostic Tests

66 Microscopy Directs Microscopy (smear) Copyright NHLS 2003 Slide 66

67 What is microscopy? Also known as direct Two methods of staining specimens o Ziel-Neelsen o Fluorescent auramine staining Dead bacilli on slide AFBs counted under microscope number bacilli (AFB s) reflect infectivity Useful for monotoring diagnosis of smear +ve TB & identifies most infectious cases Copyright NHLS 2003 Slide 67

68 Quantitative Reporting of Microscopy Copyright NHLS 2003 Slide 68

69 Auramine neg 1 Auramine neg.pdf Copyright NHLS 2003 Slide 69

70 Auramine pos 2 Auramine Pos.pdf Copyright NHLS 2003 Slide 70

71 Cultures Cultures MGIT Copyright NHLS 2003 Slide 71

72 What is culture? Specimen processing Liquid culture medium used MGIT automated non-radiometric system uses fluorometric technology Bacilli detected within 7-35 days Much more sensitive than direct Need to confirm bacilli are MTB therefore need to do differential Copyright NHLS 2003 Slide 72

73 Differential Differential confirms if Mycobacterium TB MPT64 Antigens If no sensitivities requested Copyright NHLS 2003 Slide 73

74 MOTT.pdf

75 pos cul with diff.pdf

76 Drug Susceptibility Testing Susceptibility tests are used to determine susceptibility or resistance of bacillary strain to different TB drugs Three types of susceptibility tests o LPA for first line susceptibility test o Phenotypic susceptibility tests for others o Additional requests MGIT susceptibilty tests referred to Jhb Copyright NHLS 2003 Slide 76

77 TB Sensitivities Copyright NHLS 2003 Slide 77

78 What is Hain (Line Probe Assay) The LPA is a molecular diagnostic tool which utilises mycobacterial DNA to identify MTB. Confirms presence or absence of TB Tests first line sensitivities. Not done directly on smear neg samples. Done directly on smear pos suspects not follow up specimens. Follow up specimens: LPA done from MGIT culture. Copyright NHLS 2003 Slide 78

79 Hain (Line Probe Assay) Copyright NHLS 2003 Slide 79

80 Line Probe Assay

81 Direct +ve, PCR MTB +ve (Rif R INH R) 3 PCR pos Rif R INH R.pdf Copyright NHLS 2003 Slide 81

82 Drug Susceptibility Testing Phenotypic Susceptibility Tests Second Line DST Middlebrooks (7H11) Copyright NHLS 2003 Slide 82

83 conventional cul diff sens.pdf

84 Direct +ve PCR MTB +ve (Rif R INH S) 3 PCR pos Rif R INH S.pdf Rif Mono resistance Copyright NHLS 2003 Slide 84

85 LPA 2 neg.pdf

86 LPA 1 neg.pdf