SCREENIG FOR TOXOPLASMOSIS IN SLOVENIA

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1 SCREENIG FOR TOXOPLASMOSIS IN SLOVENIA Mr. Sc. Tjaša Žohar Čretnik, MD Vienna, 7th of april 2015

2 NATIONAL LABORATORY OF HEALTH, ENVIRONMENT AND FOOD CENTRE FOR MEDICAL MICROBIOLOGY Prvomajska Maribor Slovenia

4 DIAGNOSTIC MICROBIOLOGY IN SLOVENIA 11 diagnostic laboratories (8 in NLHEF) - appointed by Ministry of health around 400 employees (1,14% of all health care employees) (218 in NLHEF) 37 specialists on microbiology 700 methods and techniques and around tests performed per year 0,8 % of health care budget is spent on clinical microbiology testing 28 hospitals ant 74 primary health care centres

5 SEROLOGICAL TESTING FOR TOXOPLASMA INFECTION nonobligatory screening instituted in 1981 Logar J. Zdrav Vest 1981; 50: obligatory since 1995 based on estimated incidence of congenital toxoplasmosis 3/1000 live births 8 appointed laboratories (in 1998) three times during pregnancy as soon as possible -12 th week th week th week written interpretation of results by medical doctor, specialist on microbiology on the report

6 NO. OF LIVE BIRTHS ( )

SEROPREVALENCE 52 % of seropozitive pregnant women in 1980 (unpublished data) 34% out of 21270 tested (1996-1999)

7 SEROPREVALENCE 52 % of seropozitive pregnant women in 1980 (unpublished data) 34% out of tested ( ) Logar J at al., Scand J Infect Dis 2002; 34: ,8 % out of tested ( ) Brdnik J. 2008; Graduation Thesis

8 SEROPREVALENCE IN CELJE REGION ( PREGNANCIES)

9 INCREASE IN NO. OF TESTS PERFORMED (MORE THAN 40 %)

10 ACUTE INFECTIONS IN PREGNANCY Estimated burden of congenital toxoplasmosis for Slovenia by WHO - 1,9 CT cases per 1000 births Rotgerson T, Mastroiacovo P; Bull World Health Organ 2013;91: /1000 pregnant women Logar J et.al. Scand. J Infect Dis 1992; 24: /1000 pregnant women Logar J et.al. Scand. J Infect Dis 1995; 27: ,4/1000 pregnant women unpublished data 9,7/1000 pregnant women Brdnik J Graduation Thesis 2008, University of Ljubljana

11 NO. OF ALL REPORTED CASES OF ACUTE INFECTIONS Year No. of reported cases Per 1000 live births?? , (1CT) 0, , , , ,45

12 ACUTE INFECTIONS IN CELJE REGION From 2001 to pregnant women tested 48 confirmed infections (1,6/1000 pregnancies) 33 seroconversions 15 4x rise of titre all IgM, IgA positive with low avidity of IgG 56 cases positive for IgM, IgA, low avidity of IgG and no dynamic in titre (1,9/1000 pregnancies) No cases of symptomatic congenital toxoplasmosis

13 UNVANTED TEST RESULTS False positive IgG result lost from further screening unrecognized infection False negative IgM result missed acute infection in early phase (delay of 3 months) False positive IgM result fear, unnecessary additional testing False negative IgG result unnecessary additional testing Screenings regarded as business opportunities everybody wants to do it!

14 QUESTIONS FOR LABORATORIES Which test is good enough? validation - producer 93,3-100% spcificity 77,5-99,1% sensitivity for IgM tests (by FDA) verification published articles demonstration by laboratory Are they equivalent and how to compare them? What kind of additional testing is necessary?

15 COMPARISON OF PARTICIPANTS IN EQA Two different testing systems (A and B) From scored test results analysed

16 test parameter IgG positive IgG negative IgM positive IgM negative A No. of results No. of correct results % of correct results 96,84 99,41 98,65 99,38 No. of incorrect results % of incorrect results 0,40 0,41 0,73 0,40 No. of equivocal results % of equivocal results 2,76 0,18 0,62 0,22 B No. of results No. of correct results % of correct results 97,16 96,75 89,01 97,13 No. of incorrect results % of incorrect results 0,88 1,90 2,06 1,90 No. of equivocal results % of equivocal results 1,96 1,35 8,93 0,97

17 CONSEQUENCES OF DIFFERENT PERFORMANCE 0,41 % versus 1,9 % false positive IgG results (4X) 0,40 % versus 1,9 % false positive IgM results (4x) 0,40 % versus 0,88% false negative IgG results (2x) 0,73 % versus 2,06 % false negative IgM result (3x)

18 ADDITIONAL TESTING TO AVOID FALSE RESULTS False positive IgG result IIF in sera with reactivity from1-15 IU/ml False negative IgM result avidity of IgG in sera with high negative IgM results (OD from 0,3 to 0,55) another IgM test if IgG is negative False positive IgM result confirmation of positive or equivocal IgM result with another test (ELISA, WB) avidity of IgG in all sera positive or equivocal for IgM False negative IgG result IIF in sera with reactivity from1-15 IU/ml All control samples tested in paralel (in the same run) IIF, IgM, IgA, WB

19 CONCLUSIONS Strict reporting Collection of national data Testing performed in limited number of appointed laboratories which work in close cooperation Set price

UKNEQAS Toxoplasma Serology. It is the fault of the kits or is it?

UKNEQAS Toxoplasma Serology. It is the fault of the kits or is it? UKNEQAS Toxoplasma Serology It is the fault of the kits or is it? Purpose of the Schemes The Toxoplasma subschemes consist of IgG and IgM and are designed to: Provide information allowing participants