How do pregnancy tests work? - Tien Nguyen

Kako funkcioniše test na trudnoću? - Tjen Ngajen (Tien Nguyen)

Prevodilac: Ivana Krivokuća Lektor: Tijana Mihajlović

The earliest known pregnancy test dates back to 1350 BC in Ancient Egypt.

Najstariji poznati test za trudnoću

datira još iz 1350. godine p.n.e. u starom Egiptu.

According to the Egyptians,

Prema Egipćanima,

all you have to do is urinate on wheat and barley seeds, and wait.

sve što treba da uradite je da mokrite na semenju pšenice i ječma i sačekate.

Ako bilo koje od njih nikne, čestitamo, trudni ste!

If either sprouts, congratulations, you're pregnant!

And if wheat sprouts faster, it's a girl, but if barley, it's a boy.

Ako pšenica klija brže, devojčica je, ali ako je ječam brži, onda je dečak.

In 1963, a small study reproduced this test

Godine 1963, manje istraživanje je ponovilo ovaj test

and found that it predicted pregnancy with a respectable 70% accuracy,

i otkrilo da predviđa trudnoću sa pristojnih 70% tačnosti,

though it couldn't reliably tell the sex of the baby.

mada ne može pouzdano da pokaže pol bebe.

Scientists hypothesized that the test worked

Naučnici su postavili hipotezu da je test uspeo

because pregnant women's urine contains more estrogen,

jer urin trudnih žena sadrži više estrogena,

which can promote seed growth.

koji može podstaći rast semena.

Now it's easy to take this ancient method for granted

Lako je uzeti ovaj drevni metod zdravo za gotovo

because modern pregnancy tests give highly accurate results within minutes.

jer savremeni testovi na trudnoću daju vrlo precizne rezultate za par minuta.

So how do they work?

Pa, kako oni rade?

Svi testovi na trudnoću dostupni u slobodnoj prodaji

Over-the-counter pregnancy tests are all designed to detect one thing:

su dizajnirani tako da otkriju jedno:

a hormone called HCG.

hormon zvani HCG.

HCG is produced in the earliest stages of pregnancy

HCG se proizvodi u najranijim fazama trudnoće

and starts a game of telephone

i započinje igrom telefona

that tells the body not to shed the inner lining of the uterus that month.

koja govori telu da ne odbacuje unutrašni sloj zida materice tog meseca.

Dok trudnoća napreduje,

As the pregnancy progresses,

HCG supports the formation of the placenta,

HCG potpomaže stvaranje placente,

which transfers nutrients from mother to fetus.

koja prenosi hranljive materije od majke do fetusa.

The test starts when urine is applied to the exposed end of the strip.

Test počinje kada se urin nanese na izloženi kraj trake.

Dok tečnost putuje kroz upijajuća vlakna,

As the fluid travels up the absorbent fibers,

it will cross three separate zones, each with an important task.

preći će tri odvojene zone, od kojih svaka ima važan zadatak.

When the wave hits the first zone, the reaction zone,

Kada talas udari prvu zonu, zonu reakcije,

Y-shaped proteins called antibodies will grab onto any HCG.

proteini u obliku slova Y zvani antitela zgrabiće svaki HCG.

Attached to these antibodies is a handy enzyme

Za ta antitela je prikačen koristan enzim

with the ability to turn on dye molecules, which will be crucial later down the road.

sa sposobnošću da uključi molekule boje, što će kasnije biti od ključnog značaja.

Then the urine picks up all the AB1 enzymes

Zatim urin pokupi sve AB1 enzime

and carries them to the test zone, which is where the results show up.

i odnosi ih u zonu za testiranje, a to je tamo gde se rezultati prikazuju.

Secured to this zone are more Y-shaped antibodies

Za ovu zonu su osigurana dodatna antitela u obliku slova Y

that will also stick to HCG on one of its five binding sites.

koja će se takođe zakačiti za HCG

na jednom od njegovih pet mesta za vezivanje.

Scientists call this type of test a sandwich assay.

Naučnici zovu ovu vrstu testa „sendvič test“.

If HCG is present, it gets sandwiched between the AB1 enzyme and AB2,

Ako je HCG prisutan, dospeće u sendvič između enzima AB1 i AB2,

i zalepiti se za zonu testiranja,

and sticks to the test zone,

allowing the attached dye-activating enzyme to do its job

omogućivši prikačenom enzimu koji aktivira boju da vrši svoj posao

and create a visible pattern.

i stvori vidljivu šaru.

If there's no HCG, the wave of urine and enzymes just passes on by.

Ako nema HCG-a, talas urina i enzima samo prođe.

Finally, there's one last stop to make, the control zone.

Konačno, postoji još jedno stajalište, kontrolna zona.

As in any good experiment,

Kao i u svakom dobrom eksperimentu,

this step confirms that the test is working properly.

ovaj korak potvrđuje da test radi ispravno.

Whether the AB1 enzymes never saw HCG,

Bilo da AB1 enzimi nikada nisu videli HCG,

or they're extras because Zone 1 is overstocked with them,

ili predstavljaju višak jer je prva zona prenatrpana njima,

all the unbound AB1 enzymes picked up in Zone 1 should end up here

svi nevezani AB1 enzimi preuzeti iz Zone 1 treba da na kraju dospeju ovde

and activate more dye.

i aktiviraju još boje.

So if no pattern appears, that indicates that the test was faulty.

Ako se ne pojavi slika, to pokazuje da je test neispravan.

These tests are pretty reliable, but they're not failproof.

Ovi testovi su prilično pouzdani, ali nisu nepogrešivi.

For instance, false negatives can occur

Na primer, lažni negativni rezultat se može desiti

if concentrations of HCG aren't high enough for detection.

ako koncentracija HCG-a nije dovoljno visoka da bi bio otkriven.

After implantation, HCG levels double every two to three days,

Nakon usađivanja, nivo HCG-a se udvostručuje na svaka dva do tri dana,

so it may just be too early to tell.

tako da bi moglo biti prerano da bi se pokazalo.

And beverages can dilute the urine sample,

Takođe, napici mogu razblažiti uzorak urina,

which is why doctors recommend taking the test first thing in the morning.

zbog čega doktori preporučuju korišćenje testa

ujutru odmah po ustajanju.

On the other hand, false positives can come from other sources of HCG,

Sa druge strane, lažni pozitivni rezultat se može javiti usled drugih izvora HCG-a

like IVF injections, ectopic pregnancies,

kao što su injekcije za vantelesnu oplodnju,

vanmaterične trudnoće,

or certain cancers such as uterine cancer or testicular cancer,

ili određene vrste raka kao što je rak materice ili rak testisa,

making it possible for one of these tests to tell a man he's pregnant.

što omogućava da test ustanovi da je muškarac trudan.

The best way for a woman to find out for sure is at the doctor's office.

Najbolji način da žena otkrije zasigurno je u doktorskoj ordinaciji.

The doctors are also looking for HCG,

Doktori takođe tragaju za HCG-om,

but with tests that are more sensitive and quantitative,

ali pomoću testova koji su osetljiviji i kvantitativni

which means they can determine the exact level of HCG in your blood.

što znači da mogu da ustanove tačan nivo HCG-a u vašoj krvi.

A few minutes can feel like forever

Nekoliko minuta se mogu činiti kao večnost

when you're waiting on the results of a pregnancy test.

kada iščekujete rezultate testa na trudnoću.

But in that brief time, you're witnessing the power of the scientific method.

Ipak, u tako kratkom vremenu, svedok ste moći naučne metode.

That one little stick lets you ask a question,

Taj jedan mali štapić vam daje da postavite pitanje,

perform a controlled experiment,

izvršite kontrolisani eksperiment,

and then analyze the results to check your original hypothesis.

a zatim analizirate rezultate da biste proverili svoju prvobitnu hipotezu,

And the best part is you won't even have to wait until the next harvest.

a najbolji deo je da ne morate čak ni da čekate sledeću žetvu.