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Lateral flow - how quickly was it positive ?

14 replies

DinosaurDiana · 12/06/2021 07:30

I’m doing lateral flows twice a week for work, and the instructions say to read the result after 30 mins. I was just wondering at what point your test showed it was positive if you’ve had a positive test ?

OP posts:
Lockheart · 12/06/2021 07:40

Per the instructions in the kit, you should wait for 20-30 minutes.

DinosaurDiana · 12/06/2021 07:45

I’m not asking what the instructions are, I’m asking anyone who has had a positive test at what point they saw it.

OP posts:
PineappleAce · 12/06/2021 07:47

I'd be interested to know this too. The control line can usually be read with in a couple of minutes and it's easy to assume that the Test line would also have shown in the same timeframe.

ThorFull · 12/06/2021 07:51

I wondered too. They always remind me of pregnancy tests which turned positive immediately.

LouLou198 · 12/06/2021 07:51

When we were all positive last year it showed up as quick as the control line did, literally a few minutes. On subsequent tests we have waited the full 30 minutes just in case.

Abraxan · 12/06/2021 07:51

@PineappleAce

I'd be interested to know this too. The control line can usually be read with in a couple of minutes and it's easy to assume that the Test line would also have shown in the same timeframe.
On a pregnancy test a positive often takes longer to develop than the test line.

I know they are different and in no way the same, but assume the delay may be because of the way the two chemicals (control and result) are processed/read.

20thCenturyGhosts · 12/06/2021 08:01

The reason you have to wait the full 30 minutes is because it can show positive (falsely) before it changes to negative at the 30 minute mark.

RuthW · 12/06/2021 08:08

My daughter's positive came up in seconds

ShakespearesSisters · 12/06/2021 08:23

From my friend who tested her asymptomatic son (age 2) as he had been at the childminder with a confirmed positive case, the line came up as it was passing the area before the control came up. They then got him a pcr and isolated themselves, my friend was 7 weeks post 1st jab (we work in healthcare) and continued with her lateral flow tests and then got a positive one 5 days after her son. (Husband 4 days) they were both asymptomatic at that point. The lateral flow registered positive within about 30 seconds and then the control came up. A few days later her husband was bed riden with symptoms. Her symptoms started a day or so later but v v mild.
Another friend works at a school and was supervising the LFT there. She was always concerned that they didn't work. But when they got two positives they pinged up very quickly. Confirmed with PCR.

TheVolturi · 12/06/2021 14:28

Ds had a positive, and it was positive almost straight away, you could see the line as the strip was still soaking if you know what I mean.

AbsolutelyPatsy · 12/06/2021 14:48

i always understood you should not look much after 30 minutes, currently doing one, have a timer on,
after 30 minutes, look at result,
input onto computer/app and throw test away

mrshoho · 12/06/2021 14:52

@20thCenturyGhosts

The reason you have to wait the full 30 minutes is because it can show positive (falsely) before it changes to negative at the 30 minute mark.
I did not know this.
fleecie13 · 12/06/2021 20:10

9 out of 10 times it will show up immediately. If it is a strong positive, it will be a stronger line than the control strip. However, very weak positives can take longer to develop, but will remain a weak line...

RosesandBluebells · 12/06/2021 23:58

I tested daily when went from negative to positive. The first positive was faint, took a few mins to appear and it was a squinter. It was clearer once 30 mins were up.

It was two days before it became a blazing , darker than control line positive that appeared pretty much instantly.

9 days on and it’s fainter than my first test (I was nosey) but again still can see once 30 mins are up.

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