{"id":3805,"date":"2021-01-13T07:48:08","date_gmt":"2021-01-13T06:48:08","guid":{"rendered":"https:\/\/www.mc-praha.cz\/mcp\/?p=3805"},"modified":"2021-01-13T07:52:08","modified_gmt":"2021-01-13T06:52:08","slug":"antigenni-testovani-na-covid-19","status":"publish","type":"post","link":"https:\/\/www.mc-praha.cz\/mcp\/antigenni-testovani-na-covid-19\/","title":{"rendered":"Antigenn\u00ed testov\u00e1n\u00ed na COVID-19"},"content":{"rendered":"

V\u010dasn\u00e9 testov\u00e1n\u00ed osob na pr\u016fkaz viru SARS-CoV-2 s pou\u017eit\u00edm ov\u011b\u0159en\u00fdch metod a p\u0159esn\u00fdch postup\u016f je z\u00e1kladn\u00ed strategi\u00ed boje s\u00a0onemocn\u011bn\u00edm COVID-19. C\u00edlem testov\u00e1n\u00ed je detekce a izolace pozitivn\u00edch jedinc\u016f, kter\u00e1 zabr\u00e1n\u00ed dal\u0161\u00edmu \u0161\u00ed\u0159en\u00ed viru v\u00a0populaci. Sou\u010d\u00e1st\u00ed t\u00e9to strategie je i monitoring epidemiologick\u00e9 situace na \u00fazem\u00ed jednotliv\u00fdch region\u016f i st\u00e1t\u016f po cel\u00e9m sv\u011bt\u011b.<\/p>\n

Doposud se pro testov\u00e1n\u00ed onemocn\u011bn\u00ed COVID-19 nejv\u00edce vyu\u017e\u00edv\u00e1 metody reverzn\u00ed transkripce a\u00a0polymer\u00e1zov\u00e9 \u0159et\u011bzov\u00e9 reakce v\u00a0re\u00e1ln\u00e9m \u010dase (RT-PCR) biologick\u00fdch vzork\u016f z\u00edskan\u00fdch nasofarynge\u00e1ln\u00edm st\u011brem. Metoda RT-PCR je zalo\u017eena na detekci virov\u00e9 ribonukleov\u00e9 kyseliny (RNA) a vyzna\u010duje se vysokou senzitivitou i\u00a0specificitou. Vy\u017eaduje pat\u0159i\u010dn\u00e9 laboratorn\u00ed vybaven\u00ed nezbytn\u00e9 pro extrakci virov\u00e9 RNA z\u00a0odebran\u00e9ho vzorku a\u00a0amplifikaci gen\u016f \u010di\u00a0jejich \u010d\u00e1st\u00ed specifick\u00fdch pro nov\u00fd koronavirus. Proveden\u00ed testu metodou RT-PCR je \u010dasov\u011b n\u00e1ro\u010dn\u011bj\u0161\u00ed (trv\u00e1 obvykle n\u011bkolik hodin), dobu zpracov\u00e1n\u00ed nav\u00edc prodlu\u017euje p\u0159eprava vzork\u016f do laborato\u0159\u00ed, jejich\u017e kapacity v\u010detn\u011b kvalifikovan\u00e9ho person\u00e1lu jsou omezen\u00e9. Celosv\u011btov\u00fd n\u00e1r\u016fst p\u0159\u00edpad\u016f COVID-19 na podzim roku 2020 dramaticky zv\u00fd\u0161il popt\u00e1vku po diagnostick\u00fdch testech. Pot\u0159eba anal\u00fdzy velk\u00e9ho mno\u017estv\u00ed vzork\u016f a p\u0159et\u00ed\u017een\u00ed laborato\u0159\u00ed n\u00e1sledovan\u00e9 prodlou\u017een\u00edm term\u00edn\u016f dod\u00e1n\u00ed v\u00fdsledk\u016f vedly k\u00a0zaveden\u00ed antigenn\u00edch test\u016f jako dopl\u0148ku k\u00a0test\u016fm RT-PCR.<\/p>\n

Antigenn\u00ed testy rovn\u011b\u017e pat\u0159\u00ed mezi testy p\u0159\u00edm\u00e9ho pr\u016fkazu viru, tedy slou\u017e\u00ed k\u00a0p\u0159\u00edm\u00e9 identifikaci mikroorganismu v odebran\u00e9m vzorku. Na rozd\u00edl od testu RT-PCR v\u0161ak nedetekuj\u00ed virovou RNA, ale specifickou proteinovou strukturu viru, tzv. antigen. V\u00a0porovn\u00e1n\u00ed s\u00a0RT-PCR testy jsou antigenn\u00ed testy m\u00e9n\u011b citliv\u00e9. Tuto nev\u00fdhodu v\u0161ak vyva\u017euje mo\u017enost rychl\u00e9ho z\u00edsk\u00e1n\u00ed v\u00fdsledku (do 15\u201330 min po odb\u011bru vzorku), jednoduchost proveden\u00ed testu bez nutnosti laboratorn\u00edho vybaven\u00ed (jednor\u00e1zov\u00e1 testovac\u00ed sada), a\u00a0d\u00e1le i n\u00edzk\u00e1 cena.<\/p>\n

Krom\u011b zm\u00edn\u011bn\u00e9 ni\u017e\u0161\u00ed citlivosti se v\u0161ak s\u00a0antigenn\u00edmi testy poj\u00ed i n\u011bkter\u00e9 dal\u0161\u00ed nev\u00fdhody. Je t\u0159eba p\u0159ipomenout, \u017ee doposud nen\u00ed validovan\u00fd jednotn\u00fd postup pro klinick\u00fd odb\u011br nasofarynge\u00e1ln\u00edch vzork\u016f. Rozd\u00edly v\u00a0proveden\u00ed odb\u011bru jsou patrn\u00e9 nap\u0159\u00edklad i z\u00a0televizn\u00edch z\u00e1b\u011br\u016f z\u00a0r\u016fzn\u00fdch odb\u011brov\u00fdch center po cel\u00e9m sv\u011bt\u011b. P\u0159itom, jak uv\u00e1d\u011bj\u00ed samotn\u00ed v\u00fdrobci, spr\u00e1vn\u00fd postup p\u0159i odb\u011bru vzorku je kl\u00ed\u010dov\u00fdm prvkem cel\u00e9ho testovac\u00edho procesu ovliv\u0148uj\u00edc\u00edm vyhodnocen\u00ed testu. Na rozd\u00edl od testu RT-PCR nen\u00ed u\u00a0antigenn\u00edch test\u016f zaveden\u00fd kontroln\u00ed mechanismus pro potvrzen\u00ed spr\u00e1vn\u011b odebran\u00e9ho vzorku.<\/p>\n

V\u00a0sou\u010dasn\u00e9 dob\u011b je na sv\u011btov\u00e9m trhu velk\u00e9 mno\u017estv\u00ed v\u00fdrobc\u016f antigenn\u00edch test\u016f. Iniciativa WHO FIND (Foundation for Innovative New Diagnostics) poskytuje p\u0159ehled test\u016f pro detekci SARS-CoV-2, kter\u00e9 ji\u017e byly uvedeny na trh nebo jsou ve v\u00fdvoji. V\u00fdsledky nez\u00e1visl\u00fdch studi\u00ed nad\u00e1le ukazuj\u00ed velmi heterogenn\u00ed v\u00fdsledky senzitivity a\u00a0specificity antigenn\u00edch test\u016f ve\u00a0srovn\u00e1n\u00ed s\u00a0testy RT-PCR.<\/p>\n

V\u00fdrobci antigenn\u00edch test\u016f deklaruj\u00ed hodnoty senzitivity a specificity t\u011bchto test\u016f. Senzitivita testu vyj\u00e1d\u0159en\u00e1 v\u00a0procentech ud\u00e1v\u00e1 v\u00fd\u0161i pravd\u011bpodobnosti, \u017ee v\u00fdsledek testu bude pozitivn\u00ed v p\u0159\u00edpad\u011b, kdy je testovan\u00e1 osoba skute\u010dn\u011b nemocn\u00e1 (z\u00e1chyt infikovan\u00e9 osoby). Specificita testu je procentu\u00e1ln\u011b vyj\u00e1d\u0159en\u00e1 pravd\u011bpodobnost negativn\u00edho v\u00fdsledku testu, pokud je testovan\u00e1 osoba zdrav\u00e1 (rozpozn\u00e1n\u00ed zdrav\u00e9ho jedince). Tyto hodnoty b\u00fdvaj\u00ed p\u0159ed uveden\u00edm test\u016f na trh ov\u011b\u0159ov\u00e1ny a\u00a0validov\u00e1ny nez\u00e1vislou t\u0159et\u00ed stranou. Vzhledem k\u00a0nal\u00e9hav\u00e9 pot\u0159eb\u011b v\u0161ak byla v\u011bt\u0161ina antigenn\u00edch test\u016f schv\u00e1lena ve zrychlen\u00e9m procesu, kdy uveden\u00e9 parametry testu deklaruje pouze v\u00fdrobce.<\/p>\n

Evropsk\u00e9 st\u0159edisko pro prevenci a kontrolu nemoc\u00ed (ECDC) provedlo n\u011bkolik anal\u00fdz klinick\u00e9ho hodnocen\u00ed v\u00fdkonu komer\u010dn\u00edch antigenn\u00edch test\u016f na detekci SARS-CoV-2. Nez\u00e1visl\u00e1 hodnocen\u00ed prob\u00edhala v n\u011bkolika zem\u00edch, p\u0159ev\u00e1\u017en\u011b u symptomatick\u00fdch jedinc\u016f. V\u00fdsledky jsou n\u00e1sleduj\u00edc\u00ed: senzitivita test\u016f se pohybovala mezi 29\u201393,9\u00a0% a specifita test\u016f mezi 80,2\u2013100\u00a0%. Podstatn\u00e9 rozd\u00edly lze \u010d\u00e1ste\u010dn\u011b vysv\u011btlit r\u016fznou f\u00e1z\u00ed onemocn\u011bn\u00ed osob v\u00a0\u010dase testov\u00e1n\u00ed, z\u00e1rove\u0148 v\u0161ak odr\u00e1\u017eej\u00ed i nejednotnou kvalitu test\u016f r\u016fzn\u00fdch v\u00fdrobc\u016f.<\/p>\n

Z v\u00fd\u0161e uveden\u00fdch d\u016fvod\u016f ECDC doporu\u010duje, aby \u010dlensk\u00e9 st\u00e1ty EU provedly vlastn\u00ed nez\u00e1visl\u00e9 validace antigenn\u00edch test\u016f p\u0159ed jejich zaveden\u00edm do klinick\u00e9 praxe. V\u00fdb\u011br vhodn\u00fdch test\u016f je ponech\u00e1n na jednotliv\u00fdch st\u00e1tech jako sou\u010d\u00e1st jejich n\u00e1rodn\u00ed kompetence pro organizaci a poskytov\u00e1n\u00ed zdravotnick\u00fdch slu\u017eeb a\u00a0l\u00e9ka\u0159sk\u00e9 p\u00e9\u010de.<\/p>\n

N\u011bkter\u00e9 st\u00e1ty EU, Velk\u00e1 Brit\u00e1nie a Austr\u00e1lie zve\u0159ejnily na str\u00e1nk\u00e1ch sv\u00fdch ministerstev zdravotnictv\u00ed v\u00fdsledky vlastn\u00edch hodnocen\u00ed r\u016fzn\u00fdch antigenn\u00edch test\u016f v\u010detn\u011b doporu\u010den\u00ed pro jejich pou\u017eit\u00ed v\u00a0klinick\u00e9 praxi.<\/p>\n

V\u00a0\u010cesk\u00e9 republice mohou b\u00fdt na z\u00e1klad\u011b opat\u0159en\u00ed vydan\u00e9ho Ministerstvem zdravotnictv\u00ed \u010cR pou\u017e\u00edv\u00e1ny pouze testy s\u00a0CE-IVD certifikac\u00ed s minim\u00e1ln\u00ed senzitivitou 90\u00a0% a minim\u00e1ln\u00ed specifitou 97\u00a0%. Rovn\u011b\u017e bylo provedeno n\u011bkolik studi\u00ed porovn\u00e1vaj\u00edc\u00edch tyto parametry u vybran\u00fdch antigenn\u00edch test\u016f1<\/sup>. Bylo konstatov\u00e1no, \u017ee u r\u016fzn\u00fdch v\u00fdrobc\u016f se hodnoty senzitivity i\u00a0specificity li\u0161\u00ed, a je proto nutn\u00e9 pou\u017e\u00edvat testy s\u00a0vyhovuj\u00edc\u00edmi parametry. Bohu\u017eel, v\u00fdsledky v\u011bt\u0161iny \u010desk\u00fdch studi\u00ed neobsahuj\u00ed n\u00e1zvy v\u00fdrobc\u016f, jejich\u017e produkty byly ov\u011b\u0159ov\u00e1ny.<\/p>\n

St\u00e1tn\u00ed zdravotn\u00ed \u00fastav (SZ\u00da) uv\u00e1d\u00ed, \u017ee antigenn\u00ed testy mohou za ur\u010dit\u00fdch okolnost\u00ed nejcitliv\u011bj\u0161\u00ed metodiku RT-PCR nahradit. V regionech s vysokou prevalenc\u00ed onemocn\u011bn\u00ed COVID-19 lze jejich pomoc\u00ed vyhledat jedince s\u00a0vysok\u00fdm p\u0159enosov\u00fdm potenci\u00e1lem, co\u017e m\u016f\u017ee p\u0159isp\u011bt k\u00a0men\u0161\u00edmu tlaku na kapacitu laborato\u0159\u00ed a\u00a0zdravotnick\u00fdch za\u0159\u00edzen\u00ed. V takov\u00e9 chv\u00edli m\u016f\u017ee b\u00fdt riziko fale\u0161n\u011b negativn\u00edch v\u00fdsledk\u016f vyv\u00e1\u017eeno mo\u017enost\u00ed proveden\u00ed velk\u00e9ho mno\u017estv\u00ed screeningov\u00fdch test\u016f s\u00a0rychl\u00fdm v\u00fdsledkem. SZ\u00da upozor\u0148uje, \u017ee p\u0159i\u00a0interpretaci v\u00fdsledku antigenn\u00edho testu je pot\u0159eba zohlednit n\u00e1sleduj\u00edc\u00ed informace:<\/p>\n