The rapidly-spreading new coronavirus has put test kits at the center of how infected patients are diagnosed, so they can get treatment quickly.

為了檢測出快速散播的新冠病毒，這種篩檢試劑變得十分重要，讓確診患者得以儘快接受治療。

But there's one issue with these nose and throat-swabbing tests.

但這種鼻喉篩檢的方式有個問題。

The results aren't always accurate.

結果不一定準確。

At the center of the epidemic in Wuhan, some people tested negative, only later to find out that they actually have the disease.

在疫情的中心，武漢，有些人檢測陰性，但過一陣子後發現其實為陽性。

In the U.S., the CDC sent out test kits to public health labs that gave inconclusive results in the verification process.

美國疾管局將檢測試劑送到公共衛生實驗室，但結果皆不明確。

The unreliability of these tests even forced Chinese health officials to expand how they classify patients, which resulted in a surge of more than 14,000 cases in one day.

這些檢測的不確定性，迫使了中國衛生官員擴增了他們分類患者的方式，這使得某一天當天增加了超過 14,000 例的確診。

They are now including results from test kits and other diagnostic methods like chest scans.

除了檢測試劑，他們現在將其他檢測方式也列入觀察，如胸腔掃描。

So how do these test kits exactly work, and why are there so many problems?

這些檢測試劑究竟是如何運作的，又為何問題那麼多？

This government lab in Singapore has produced test kits for the country's public hospitals.

新加坡的這家國家實驗室，為它們的公立醫院製造檢測試劑。

It's also shipped about 10,000 tests to China.

它們也運送了約 10,000 劑給中國。

Dr. Sidney Yee leads the team that developed them.

Sidney 醫師是領導研發試劑團隊的人。

She says most doctors use a type of lab test called RT PCR, which can be used to detect small amounts of pathogens including viruses like HIV.

她說，大部分的醫師都使用一種檢測法叫 RT PCR，可以用來偵測小量病原體，包含愛滋病毒。

So this is the gold standard that's being used.

這是這種檢測的黃金標準。

What it does is, it actually directly detects the presence of the pathogen.

它可以直接偵測出病原體的存在。

It's pretty easy to use.

使用方法很簡單。

A doctor collects samples from a patient by swabbing the nose or throat for mucus.

醫師從病患的鼻腔或喉嚨裡蒐集黏液樣本。

Those swabs are then sent to a lab for a test that detects the genetic material of a pathogen.

這些黏液會被送到實驗室，來檢測是否有病原體的遺傳基因。

The sample is first mixed with reagents in a tube, then put into a machine that duplicates the genetic material.

樣本在一開始會在試管內與試劑混合，然後放至一台能複製遺傳基因的機器中。

So if the virus exists, these copies will amplify its presence, confirming that a patient has tested positive for the coronavirus.

因此，如果真有該病毒，這些複製基因能放大它們的存在，因而確診該病患已患有新冠肺炎。

Dr. Yee says the first place for error could be at the swabbing stage.

Yee 醫師表示，第一個可能發生錯誤的地方在採集黏液的時候。

Most of the time, the sampling for COVID-19 comes from a throat swab.

新冠病毒的樣本大多來自喉嚨黏液。

COVID-19 is actually a lung infection disease, so doing the throat swab really depends on how much of the pathogen you're able to capture.

新冠病毒是種肺部感染的疾病，所以做喉部黏液採樣時，真的就看你能挖到多少病原體。

Another place for error is the time it takes for the sample to reach the lab.

另一個可能出錯的地方是樣品送到實驗室得花的時間。

The pathogen on the swab is not going to last for many, many hours, so that transportation, the logistics, is also important.

黏液中的病原體並沒辦法存活太久，所以運輸、物流也很重要。

Transportation is a huge hurdle in Wuhan, where the city has been on lockdown since mid-January.

武漢的運輸有個大阻礙，因為這座城市從一月中便封城了。

When the sample gets to the lab, what is the infrastructure of the lab that is able to deal with running tests, as well as the expertise and the experience of the lab technicians that are running these tests?

當樣本送到實驗室，實驗室有什麼設施可以用來運行檢測，或有什麼專家可以來執行呢？

Dr. Yee says the most critical moment for human error is when doctors decide to use the test kit.

Yee 醫師說，人為錯誤最常發生的時候，就是當醫生決定使用篩檢試劑的時候。

For instance, many people have been showing mild symptoms, but that doesn't mean they don't have the pathogen.

舉例來說，許多人只有輕微症狀，但這不表示他們沒有病原體。

It's very hard to make the direct correlation between what our test kit can be used, on which stage of the disease progression, with respect to how much the pathogen is present in the patients.

對於篩檢試劑能夠使用的時機，如在肺炎的哪個階段，與患者體內病原體的數量，這兩者之間的關聯還很難下結論。

Just how accurately these test kits are being used is on trial in Wuhan.

這些篩檢試劑的準確率如何，還在武漢作測試。

Here, hospitals have been overstretched with limited resources.

在此處，在有限的資源下，醫院的人力、物資都非常短缺。

There are not enough staff to swab patients, and labs are inundated with the backlog of samples that wait to be tested.

沒有足夠的員工來採集患者樣本，而實驗室裡頭，又有無數堆積的樣本等著被檢驗。

There are many, many different steps, and different processes involved in just running a test.

光是運行一個檢測，就有許多不同步驟與程序。

It's not just, with respect to the test kit itself.

並不只是跟檢測試劑有關。