Interpreting QuickVue COVID-19 test
December 25, 2021 11:09 AM Subscribe
Family are planning to visit this afternoon (after driving several hundred miles), and in preparation our household took QuickVue rapid COVID-19 AG tests. We're a little confused about the results.
Both test strips show what look like clear pink lines, but at the bottom of the test strip in an area that might be intended to be beneath the black slip of plastic bearing the arrows indicating "this end into the reagent." This piece of plastic is mobile--it seems like it's stuck to the strip with goo after soaking in the reagent--and slipped down a bit when we picked the strips out to look at them.
Images here.
The accompanying instructions say "A POSITIVE result must show BOTH a BLUE line and a PINK line near the BLUE line" and "Look closely! Even a very faint, pink Test Line and a blue Control Line is a POSITIVE result. The intensity of the lines may vary." Our pink lines are not where the line is in the illustrations--it looks like the pink test line should be about a half centimeter below the blue control line. Ours are all the way at the bottom of the strip.
Additionally, Google autocompletes a search for "quickvue positive covid test line at bottom" which suggests other people have the same question, but none of the results provided any helpful information. Can anyone point us toward anything about the correct way to interpret these lines?
(We're looking into getting in-person rapid tests but it may not be possible before family arrives.)
Both test strips show what look like clear pink lines, but at the bottom of the test strip in an area that might be intended to be beneath the black slip of plastic bearing the arrows indicating "this end into the reagent." This piece of plastic is mobile--it seems like it's stuck to the strip with goo after soaking in the reagent--and slipped down a bit when we picked the strips out to look at them.
Images here.
The accompanying instructions say "A POSITIVE result must show BOTH a BLUE line and a PINK line near the BLUE line" and "Look closely! Even a very faint, pink Test Line and a blue Control Line is a POSITIVE result. The intensity of the lines may vary." Our pink lines are not where the line is in the illustrations--it looks like the pink test line should be about a half centimeter below the blue control line. Ours are all the way at the bottom of the strip.
Additionally, Google autocompletes a search for "quickvue positive covid test line at bottom" which suggests other people have the same question, but none of the results provided any helpful information. Can anyone point us toward anything about the correct way to interpret these lines?
(We're looking into getting in-person rapid tests but it may not be possible before family arrives.)
On your instruction sheet in step 10, it says to put your test strip on the outline and that’s how to gauge where that pink line should be as well as where the arrow part that peeled off should be. I would interpret your test as negative and agree with DarlingBri that the pink is the reagent line.
posted by kimberussell at 11:21 AM on December 25, 2021 [3 favorites]
posted by kimberussell at 11:21 AM on December 25, 2021 [3 favorites]
If I see pink shading on the strip bordering the black label, is this a positive result?Seems pretty clear that this is not a positive.
Only a pink line about half of a centimeter below the blue control line should be considered a positive result. A pink line bordering the black label with the arrows, a vertical pink line, or a faint grey line next to the blue control line is not considered a positive test line and should not be called a positive result.
posted by ssg at 11:27 AM on December 25, 2021 [5 favorites]
You're not the only people to have this confusion, to the extent that one of the country's most vocal COVID testing authorities just tweeted about it yesterday. He says, "When a QuickVue test is pos, the pink line generally forms about 1/3 of an inch or so below the blue control line." That's not what you have.
Whether you want to treat that as a negative or as an invalid test and test again is I suppose up to you and how many tests you have on hand. They're not the best designed tests unfortunately.
posted by zachlipton at 11:31 AM on December 25, 2021 [5 favorites]
Whether you want to treat that as a negative or as an invalid test and test again is I suppose up to you and how many tests you have on hand. They're not the best designed tests unfortunately.
posted by zachlipton at 11:31 AM on December 25, 2021 [5 favorites]
My mom had the same thing happen. She called the manufacturer's customer service line and got right through. They told her it's a known issue and she's negative. I believe that half a centimer is the distance they told her, from the control line to indicate a positive result.
posted by happy_cat at 9:35 PM on December 25, 2021 [3 favorites]
posted by happy_cat at 9:35 PM on December 25, 2021 [3 favorites]
I have a collection of 4 of these, all negative. Looking at them just now, I was able to peel back the top of the arrows, and confirmed that I also have a pink line where you do. That line would definitely not be visible if the arrows had not separated from the strip.
posted by joeyh at 1:58 PM on December 26, 2021
posted by joeyh at 1:58 PM on December 26, 2021
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posted by DarlingBri at 11:15 AM on December 25, 2021 [3 favorites]