Uma sizwa igama elithi PCR, sicabanga ngobhubhane lwe-Covid, akunjalo? Isikhathi lapho kwadingeka sifake khona i-swab ekhaleni lethu silinde umbiko ukuthi ufike... lokho ngeke kuze kukhohlakale. Kodwa bewazi ukuthi i-PCR ayisetshenziselwa nje ukuthola i-Covid? Empeleni lokhu ukuhlolwa okubaluleke kakhulu okuye kwenza intuthuko enkulu kwisayensi yezokwelapha. Ngakho-ke namuhla, ake sixoxe ngokuthi lokhu kuhlolwa kwe-PCR kuyini, yiziphi ezinye izinto okungazithola, nokuthi kusebenza kanjani ngendlela elula ongayiqonda.
Kuyini i-PCR kalula?
Kulungile, ake sikubeke ngale ndlela. Cabanga ukuthi kufanele uthole igama elilodwa ekhasini elilodwa lencwadi eyodwa, ezinkulungwaneni zezincwadi eziselayibhrari enkulu. Kungaba nzima kangakanani lokho? Kufana nokuthola ucezu oluncane lwe -DNA noma i-RNA , izinto zofuzo ezingaphakathi kwamaseli emizimbeni yethu.
Ubuchwepheshe be-PCR (Polymerase Chain Reaction) benza lowo msebenzi onzima ube lula. Lokhu okwenzayo ukukopisha ingxenye encane kakhulu ye-DNA noma i-RNA esiyifunayo amakhulu ezinkulungwane, ngisho nezigidi zezikhathi (ukukhulisa). Kufana nokuthola ikhasi elinegama encwadini yomtapo wolwazi, ukulifaka emshinini wokukopisha, nokwenza amakhophi angaba yisigidi. Khona-ke, njengoba lelo gama okunzima ukulithola selikhona yonke indawo manje, singalibona kalula.
Kalula nje, i-PCR ukuhlolwa okuthatha inani elincane kakhulu leseli emzimbeni wethu, ithonsi legazi, noma i-nasal swab, bese kukhula ngokwenziwa ingxenye ethile ye-DNA noma i-RNA kuyo elabhorethri ukuqinisekisa ukuthi ikhona yini kusampula yethu noma cha. Lokhu ukuhlolwa okubucayi kakhulu. Lokhu kusho ukuthi ingathola ngisho nenani elincane kakhulu legciwane. Le ndlela ingeyeqembu lokuhlolwa elibizwa ngokuthi i-Nucleic Acid Amplification Test (NAAT).
Yiziphi izifo ezingatholakala ngokuhlolwa kwe-PCR?
Nakuba i-PCR isithandwa kakhulu ngenxa yobhubhane lwe-COVID, ibilokhu isetshenziswa ezweni lezokwelapha amashumi eminyaka. Kunezinto eziningi ezingatholakala ngalolu vivinyo. Ake sibheke ezinye zeziyinhloko.
| Yini engabonakala | Izibonelo kanye nencazelo |
|---|---|
| Izifo Ezithelelanayo | Ingathola izifo ezibangelwa amagciwane amancane afana namagciwane, amabhaktheriya, isikhunta, kanye nezinambuzane. Isibonelo, i-PCR isetshenziselwa ukuthola ngokunembile izifo ezifana ne-COVID-19, i-dengue, i-influenza (flu), isifo sofuba, i-HIV, kanye ne-hepatitis B kanye ne-C. |
| Izifo Zofuzo | Ezinye izifo zizuzwa ngezakhi zofuzo. I-PCR isiza ekuboneni izinguquko ezithile (ukuguqulwa kwezakhi zofuzo) kulezi zakhi zofuzo. Izibonelo: I-Cystic Fibrosis, isifo sikaHuntington. |
| Umdlavuza | Lokhu kuhlolwa kungakhomba izinguquko ezithile zofuzo kumaseli omdlavuza. Lokhu kungasiza odokotela ukukhetha imithi engahlasela lowo mdlavuza (ukwelashwa okuqondiwe). |
| Ukuhlolwa Kwangaphambi Kokubeletha | Ubuchwepheshe be-PCR busetshenziswa ezivivinyweni ukuze kutholakale kusengaphambili ukuthi ingane esibelethweni sikanina inazo yini izifo zofuzo. |
| Isayensi Yezobunhloli | I-DNA ikhishwa entweni encane kakhulu yegazi noma ezinweleni ezitholakala endaweni yobugebengu, ikhuliswe kusetshenziswa ubuchwepheshe be-PCR, futhi isetshenziselwa ukuhlonza abasolwa. |
Uthatha kanjani isampula ukuze uhlolwe i-PCR?
Indlela othatha ngayo isampula ukuze uhlolwe i-PCR incike ekutheni hlobo luni lwesifo olufunayo. Indlela yokuthatha isampula ihlukile ngesimo ngasinye.
| Indlela yokuthatha amasampula | Lokhu kwenziwa ngaphansi kwaluphi uhlobo lwesimo? |
|---|---|
| Isampula yegazi (Ukuhlolwa Kwegazi) | Kuthathwa isampula yegazi ukuze kutholakale izifo zofuzo, kanye nokuthola amagciwane athile (isib. i-HIV, i-Hepatitis B/C) angene egazini. |
| I-nasopharyngeal swab | Lena yindlela esiyaziyo sonke. Uyakhumbula ukuthi wafaka induku ekhaleni lakho ngesikhathi se-Covid? Le ndlela isetshenziselwa ukuthola amagciwane athinta uhlelo lokuphefumula (i-COVID, i-Influenza, i-RSV). |
| Ukuhlolwa kwebhayoloji | Lesi sampula sithathwa engxenyeni encane yezicubu ezivela esimila somdlavuza noma emnkantsheni bese sisetshenziselwa ukubheka izinguquko zofuzo emaseli. |
| I-Amniocentesis | Lokhu kwenzelwa ukuhlola isimo sofuzo somntwana ngokuthatha inani elincane loketshezi lwe-amniotic oluzungeze umntwana kumama okhulelwe. |
| Ukuxilongwa Kwezakhi Zofuzo Ngaphambi Kokufakelwa | Ngokufakelwa kwe-in vitro (IVF), le ndlela isetshenziselwa ukuhlola amangqamuzana ambalwa avela kumbungu ukuze kubonakale ukuthi unezifo zofuzo ngaphambi kokuba ufakwe esibelethweni sikamama. |
Esikhathini esiningi, awudingi ukwenza lutho olukhethekile ukuze ulungiselele ukuhlolwa kwe-PCR. Kodwa-ke, kwezinye izimo, njengalapho wenza into efana ne-biopsy, udokotela wakho uzokunikeza imiyalelo edingekayo kusengaphambili.
Ubuchwepheshe be-PCR busebenza kanjani?
Kulungile, manje ake sibone ukuthi lobu buchwepheshe obumangalisayo busebenza kanjani ngempela. Lokhu kungokwesayensi kancane, kodwa ngizokuchaza kalula.
1. Ukulungiswa kwesampula: Okokuqala, i-DNA noma i-RNA ihlukaniswa nesampula (igazi, uketshezi, njll.) ethathwe kuwe.
2. Ukwenza ingxube: Okulandelayo, le DNA/RNA ehlukanisiwe ixutshwa namakhemikhali athile akhethekile. Into eyinhloko kule ngxube yi-enzyme ebizwa ngokuthi i-DNA Polymerase . Lena yiyona eyinhloko eyenza umsebenzi wokukopisha.
3. Umjikelezo Wokushisa Nokupholisa: Manje ithubhu elincane elinale ngxube lifakwa emshinini okhethekile. Lo mshini uphakamisa futhi wehlise izinga lokushisa ngokushesha okukhulu.
- Ukuguquka kwesimo: Okokuqala, izinga lokushisa liyakhuphuka lifike kuma-degree Celsius angaba ngu-95. Lokhu kubangela ukuthi imicu emibili ye-DNA ihlukane.
- Ukuhlanganisa: Okulandelayo, izinga lokushisa lehliswa libe cishe ama-degrees angu-55. Bese kuthi, izingcezu ezincane ze-DNA (ama-primer) ezihambisana nengxenye ye-DNA esiyifunayo zinamathiselwe emicu ye-DNA ehlukanisiwe.
- Ukuphinda Ufudumale (Ukwandiswa): Bese izinga lokushisa liphakanyiswa libe ngama-degrees angaba ngu-72. Bese i-enzyme ye-DNA polymerase ingena bese yenza umucu omusha we-DNA kuleyo primer ehambisana nomucu wokuqala we-DNA.
4. Ukukopisha: Manje sekwenziwe amakhophi amabili entambo eyodwa ye-DNA. Lo mjikelezo wokushisa uziphinda izikhathi ezingaba ngu-30-40. Emjikelezweni owodwa, inani le-DNA liphindeka kabili. Okubili kuba kane, okune kuba yisishiyagalombili, okuyisishiyagalombili kuba yishumi nesithupha... Ngemva kwemijikelezo engaba ngu-30, kwenziwe amakhophi angaphezu kwezigidigidi kusukela engxenyeni eyodwa yokuqala ye-DNA.
Manje, leso siqeshana se-DNA/RNA, esasisincane kakhulu ukuba singatholakala ngaphambili, sesisikhulu ngokwanele ukuba sitholakale kalula.
Ingabe kukhona izinhlobo zokuhlolwa kwe-PCR?
Yebo, kunezinhlobo ezimbili ikakhulukazi okudingeka siziqaphele.
- I-Reverse-transcriptase PCR (RT-PCR): Amanye amagciwane, njenge-Covid, i-influenza, kanye ne-HIV, anolwazi lwawo lwezakhi zofuzo ku-RNA kune-DNA. I-PCR evamile ingakopisha i-DNA kuphela. Ngakho-ke, okwenzayo ku-RT-PCR ukusebenzisa i-enzyme ekhethekile (`Reverse Transcriptase`) kuqala ukuze 'uguqule' leyo RNA ibe yi-DNA. I-DNA ephumayo ibizwa ngokuthi i-DNA ehambisanayo (cDNA). Bese kuba inqubo evamile ye-PCR.
- I-PCR Yesikhathi Sangempela / I-PCR Enobuningi (Q-PCR): Lena indlela ethuthuke kancane. Okwenzekayo kulokhu ukuthi njengoba i-DNA ikopishwa, ilebula le-fluorescent linamathiselwa kuyo. Njengoba inani le-DNA ekopishiwe landa, le fluorescence nayo iyanda. Umshini ungalinganisa le fluorescence. Ngakho-ke, sisalindile, okungukuthi, ngesikhathi sangempela , singabona ukuthi i-DNA efanele ikhona yini kusampula noma cha. Akukhona lokho kuphela, kunganikeza nombono oqondile wokuthi ingakanani igciwane elalikusampula yokuqala (umthwalo wegciwane). Ukuhlolwa kwe-Real-time RT-PCR okuhlanganisa zombili lezi zindlela kuvame ukusetshenziselwa ukuthola i-Covid.
Usho ukuthini umbiko we-PCR?
Kubaluleke kakhulu ukuqonda umbiko we-PCR uma uwuthola.
- Kutholakale / Kuhle: Uma umbiko wakho uthi "Kutholakale" noma "Kuhle," kusho ukuthi isampula yakho yayinezingxenye zegciwane noma izinto zofuzo ababezifuna. Kalula nje, cishe unesifo.
- Akutholakali / Kubi: Lokhu kusho ukuthi izingcezu ze-DNA/RNA ezifanele azitholakalanga kusampula ehlolwe. Lokhu kusho ukuthi cishe awunalo lelo gciwane.
Kodwa nansi into ebaluleke kakhulu. Ngezinye izikhathi, uma uhlola ezinsukwini zokuqala zokutheleleka (ikakhulukazi ngaphambi kokuba izimpawu ziqale), inani legciwane emzimbeni wakho lingase libe liphansi futhi i-PCR ingase ingaliboni. Ngakho-ke, noma ngabe uthola umphumela othi 'Awutholakali', uma usenezimpawu, kungcono ukukhuluma nodokotela wakho bese ulandela iseluleko sakhe. Ungase ucelwe ukuthi uphinde uhlolwe ezinsukwini ezimbalwa.
Isikhathi esithathayo ukuthola imiphumela siyahlukahluka kuye ngokuthi kwenziwa kanjani ukuhlolwa. Ukuhlolwa kwamakhala (njenge-COVID, i-influenza) kuvame ukuthola imiphumela zingakapheli amahora angama-24. Kodwa-ke, ukuhlolwa kwegazi kanye nokuhlolwa kwe-biopsy ukuze kubhekwe izifo zofuzo kungathatha isonto noma ngaphezulu.
Uma unemibuzo noma ukukhathazeka mayelana nokuhlolwa kwe-PCR noma imiphumela yako, qiniseka ukuthi ukhuluma nodokotela wakho ngakho.
Umlayezo Wokuya Nawe Ekhaya
- I-PCR akuyona nje ukuhlolwa kwe-COVID. Kuwukuhlolwa kwezokwelapha okunamandla kakhulu futhi okunembile okusetshenziselwa ukuxilonga izifo ezahlukahlukene, izifo zofuzo, kanye nezimo ezinjengomdlavuza.
- Lobu buchwepheshe bukopisha inani elincane kakhulu le-DNA noma i-RNA kusampula libe amakhophi ayizigidi, okulenza lifinyelele ezingeni elilula ukulibona.
- Ngisho noma umphumela we-PCR uthi "Awutholakali" (Unegative), uma unezimpawu, akusho ukuthi awunaso lesi sifo ngokuphelele. Lokhu kungaba njalo, ikakhulukazi ezigabeni zokuqala zokutheleleka.
- Udokotela wakho ungumuntu ongcono kakhulu ukuphendula noma yimiphi imibuzo noma ukukhathazeka ongase ube nakho mayelana nemiphumela yokuhlolwa kwakho kanye nesimo sakho sempilo, ngakho ungalokothi unqikaze ukukhuluma naye.
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