6 ms·

> Because $25 of electronics to read a $1 paper strip makes perfect sense in today's world I guess This makes sense, because you can calibrate the sensor in th

> Because $25 of electronics to read a $1 paper strip makes perfect sense in today's world I guess This makes sense, because you can calibrate the sensor in the factory and not worry about "is that a faint line I am seeing? Do faint lines count?" situation anymore. Converting continuous data to a simple yes/no output has value. > As does not making the strip a replaceable consumable part. This may or may not make sense based on the requirements for maintaining calibration. I am not sure about this.

arrrg 5y ago
Most certainly not at that cost. Easy access to tests is much more important than ridiculously inflated prices. There is no value at all to this, not for COVID lateral flow ag tests, it’s complete bullshit. Those tests have to be plentiful, it has to be easy to get and make one. This also seems to be the case pretty much everywhere except in the US which is so weird. I read all these discussions about lateral flow ag tests from the US and they are like from another fucking planet. Why are those so hard to get in the US? And so expensive? They are free and plentiful here (at test stations, insurance doesn’t matter) and still cheap enough in grocery stores to just have a couple dozen at home.
leoedin 5y ago
It's not hard to write "Faint lines count" in the test instructions. Any line at all is a positive test. You have to take into account the effect the extra cost has as well - if it's between doing one automated bluetooth test that costs $25 or 5 manual tests which cost $5 each - the 5 tests is clearly a better outcome for society.
- rocqua 5y ago
  What I have been wondering about is a positive line showing up after 3 hours. I've had this happen consistently, and found no indication of what to do. The official docs say any results after 30 minutes are void. But why? Does the false positive rate go up to high? What could cause false positives. I have had a few PCRs that all said negative, but the quicktest really worried me.
- nsxwolf 5y ago
  Problem is, I can often see the faint line right out of the package, before any reagent or sample is applied. I get really OCD about that.
  - dawnerd 5y ago
    The tests I have here say if you see any lines that are not the control line the test is not good. You might want to double check and contact the manufacturer.
    - nsxwolf 5y ago
      I may be imagining the lines. But there’s no difference between imagining one and seeing one when it comes to your confidence level and thus the value of the test. Google “imagining faint line” and see what a common problem it is. There was an interesting thread last week about different abilities to visualize images in your head - some people describe visualizing things in a faint sort of way, not a full on visual hallucination. Take that ability, mix it with the anxiety of fearing a test result and the tendency to second guess yourself, and I think you can see the value of electronics making the determination for you.
- wyattpeak 5y ago
  > the 5 tests is clearly a better outcome for society. I don't think that's obviously true. Misread pregnancy tests are fantastically common, and someone mistakenly believing they don't have covid is going to be a significant negative for society. Instructions simply don't work, a large number of people don't read instructions. Heck, I might not read the instructions for this if it looked understandable at first glance. Decades of pointless barely-understandable instructions on cheap devices have trained me not to bother.
  - leoedin 5y ago
    It's pretty tricky to self-administer one of these lateral flow covid tests without reading the instructions. There's a whole sequence of steps - swabbing, mixing the swab in the buffer solution, dropping a set number of drops into the sample window. This device doesn't appear to get rid of any of that complexity - instead adding significant complexity and to the simplest part of the test - look for a line.
    - alexfoo 5y ago
      Indeed, there's also considerable variability in the different lateral flow tests. If you don't read the instructions then you may not work out the differences when the next set come along. In the UK we have, amongst others I'm sure, the NHS branded boxes, Flowflex, and Orient Gene. Some require swabbing nose and throat, some are just nasal swabs. Some require 2 drops onto the device, some require 4. Some require a certain amount of time to be left in the buffer solution, others just a set of steps of pushing/turning/squeezing the swab in the buffer. Some require waiting 30 minutes (minimum), some are 15 minutes (minimum) and 30 minutes maximum. etc.
    - andybak 5y ago
      I somehow managed to miss the critical fact that the line can be very faint for quite a long time. I'm a developer. I suck at reading documentation.
- gruez 5y ago
  >if it's between doing one automated bluetooth test that costs $25 or 5 manual tests which cost $5 each - the 5 tests is clearly a better outcome for society. are we talking about doing 5 tests on the same women, or doing 5 tests on different women?
- maxsilver 5y ago
  > Any line at all is a positive test. It's not obvious what counts as a "faint line" -- is this too faint? Is it not really there? Am I misreading natural variations in the colour of the test strip? It's not a matter of reading instructions -- even intelligent adults who have followed the directions 100% correctly can still struggle with knowing what counts. Anyone who has ever taken a pregnancy test (or seen someone else take a pregnancy test), can tell you about the major amounts of stress possible attempting to read a "simple faint line" -- see https://www.reddit.com/r/TFABLinePorn/ https://www.reddit.com/r/TFABLinePorn/ for one example. I'm not saying that every test strip needs $20 of Bluetooth gizmos and e-waste. Just that normal, intelligent, fully-instruction-following adults can reasonably be expected to not always know how to read "any faint lines" accurately.
  - ethanbond 5y ago
    Not to mention motivated reasoning/perception. Is this positive test going to mean you’re going to cancel your holiday plans and lose thousands of dollars?
  - takeda 5y ago
    > It's not obvious what counts as a "faint line" -- is this too faint? Is it not really there? Am I misreading natural variations in the colour of the test strip? If you think of how the test works, then it is obvious that if you can spot the line it is positive.
    - xxpor 5y ago
      I have literally no idea how the test works; I'm a software engineer. They're supposed to be similar to pregnancy tests right? But those detect hormones afaik, not viruses (or antibodies).
      - takeda 5y ago
        The test contains antibodies for the virus, so if they react in any way (assuming you weren't tampering with it[1]) then you have the virus. Those tests are considered unreliable, because the false negative is high (i.e. not enough of the virus to register). I don't know enough about pregnancy test, but I assume the hormone is always present, it's just certain level of it signals pregnancy. [1] there were videos where people where testing juices and soft drinks and that was messing up the test.
elif 5y ago
the machine readers that doctors and hospitals use for test strips are used hundreds of times per day on multiple samples
- smnrchrds 5y ago
  I am sure reusable machines exist. What I am not sure (really not sure, it may or may not be feasible) is if they can be made at consumer-level price point and with consumer limitations (e.g. no requirement for maintenance or calibration for the lifetime of the device). I imagine the professional devices cost thousands of dollars and undergo regular maintenance.
lm28469 5y ago
> a simple yes/no output has value The line is a boolean indicator. Either it's there or it isn't. People are dumb as rocks but come on, what's the next step ? Shipping a doctor with every test ? We maybe need a bluetooth sensor in masks because apparently people don't know if they should use them above or under their nose.... I'm pretty sure our brains are more than calibrated enough to discern basic shapes and colors. These tests are an insult to our intelligence.
- gruez 5y ago
  >The line is a boolean indicator. Either it's there or it isn't. No it's not. The world is analog, not digital. The parent comment specifically mentions this: >and not worry about "is that a faint line I am seeing? Do faint lines count?" situation
  - lm28469 5y ago
    Have you used these tests ? Have you read their manuals ? Of course the world is analog, it doesn't prevent me from assessing if I have socks on or not, or if my light bulb is on or off ... Faint lines do count, as stated in the documentation, if your eyes can see something it means it's positive, that's all there is to know, these tests have been designed to be used by humans...
    - dragonwriter 5y ago
      > if your eyes can see something This is not a consistent standard from person to person.
    - lazide 5y ago
      Having used the tests multiple times (including the Ellume tests), and having Covid positive and negative results (due to a child getting it twice!! this year)? It is really hard to tell sometimes. And sometimes people don’t want to see a specific answer, and will fight over if something is positive or not. The Binax now faint line for instance can be really faint-but-still positive, and I personally got in an argument with his mom over if it counted as positive or not (day 5 and 5th positive test in a row, with decreasing line clarity each time).
simion314 5y ago
>This makes sense, because you can calibrate the sensor in the factory and not worry about "is that a faint line I am seeing? Do faint lines count?" situation anymore. Converting continuous data to a simple yes/no output has value. But can you trust this calibrations? I bought a infrared thermometer and for some fucking reason for my son always shows at least +1 degrees but is fine for everyone else in the family. I discovered this only after a few days where his fever would not calm down and I found some old thermometers and confirm that is broken(still shows fever for him a month later and I could not find any logical explanation what is special with my son)
- rootusrootus 5y ago
  AFAIK 1 degree does not count as a fever, especially in children. That's within the range of normal variation.
  - simion314 5y ago
    It is always over 38 Celsius which qualifies as fever where under the tongue is 1 degree less. So if I use it on my I get 36.4 on my son I get 38.4 , even if I try different areas of the body is still converges on the high value.
  - mc32 5y ago
    I think they’re saying it always seems to be off by one degree for their son compared to other thermometers.
- xkcd-sucks 5y ago
  Re: IR thermometers, the temperature measurement is related to surface emissivity (basically the fraction of heat that gets radiated as light), which can be pretty variable between people (skin grease, cosmetics, sweat). As well as variability in blood flow etc. if it's a forehead measurement. In the antigen test strip case one would hope the materials and lighting to be controlled, so less risk of miscalibration (even if it's a stupid way to satisfy somebody's demand for a test to be made "quantifiable")

arrrg 5y ago

Most certainly not at that cost. Easy access to tests is much more important than ridiculously inflated prices. There is no value at all to this, not for COVID lateral flow ag tests, it’s complete bullshit. Those tests have to be plentiful, it has to be easy to get and make one. This also seems to be the case pretty much everywhere except in the US which is so weird. I read all these discussions about lateral flow ag tests from the US and they are like from another fucking planet. Why are those so hard to get in the US? And so expensive? They are free and plentiful here (at test stations, insurance doesn’t matter) and still cheap enough in grocery stores to just have a couple dozen at home.

leoedin 5y ago

It's not hard to write "Faint lines count" in the test instructions. Any line at all is a positive test. You have to take into account the effect the extra cost has as well - if it's between doing one automated bluetooth test that costs $25 or 5 manual tests which cost $5 each - the 5 tests is clearly a better outcome for society.

rocqua 5y ago
What I have been wondering about is a positive line showing up after 3 hours. I've had this happen consistently, and found no indication of what to do. The official docs say any results after 30 minutes are void. But why? Does the false positive rate go up to high? What could cause false positives. I have had a few PCRs that all said negative, but the quicktest really worried me.
nsxwolf 5y ago
Problem is, I can often see the faint line right out of the package, before any reagent or sample is applied. I get really OCD about that.
- dawnerd 5y ago
  The tests I have here say if you see any lines that are not the control line the test is not good. You might want to double check and contact the manufacturer.
  - nsxwolf 5y ago
    I may be imagining the lines. But there’s no difference between imagining one and seeing one when it comes to your confidence level and thus the value of the test. Google “imagining faint line” and see what a common problem it is. There was an interesting thread last week about different abilities to visualize images in your head - some people describe visualizing things in a faint sort of way, not a full on visual hallucination. Take that ability, mix it with the anxiety of fearing a test result and the tendency to second guess yourself, and I think you can see the value of electronics making the determination for you.
wyattpeak 5y ago
> the 5 tests is clearly a better outcome for society. I don't think that's obviously true. Misread pregnancy tests are fantastically common, and someone mistakenly believing they don't have covid is going to be a significant negative for society. Instructions simply don't work, a large number of people don't read instructions. Heck, I might not read the instructions for this if it looked understandable at first glance. Decades of pointless barely-understandable instructions on cheap devices have trained me not to bother.
- leoedin 5y ago
  It's pretty tricky to self-administer one of these lateral flow covid tests without reading the instructions. There's a whole sequence of steps - swabbing, mixing the swab in the buffer solution, dropping a set number of drops into the sample window. This device doesn't appear to get rid of any of that complexity - instead adding significant complexity and to the simplest part of the test - look for a line.
  - alexfoo 5y ago
    Indeed, there's also considerable variability in the different lateral flow tests. If you don't read the instructions then you may not work out the differences when the next set come along. In the UK we have, amongst others I'm sure, the NHS branded boxes, Flowflex, and Orient Gene. Some require swabbing nose and throat, some are just nasal swabs. Some require 2 drops onto the device, some require 4. Some require a certain amount of time to be left in the buffer solution, others just a set of steps of pushing/turning/squeezing the swab in the buffer. Some require waiting 30 minutes (minimum), some are 15 minutes (minimum) and 30 minutes maximum. etc.
  - andybak 5y ago
    I somehow managed to miss the critical fact that the line can be very faint for quite a long time. I'm a developer. I suck at reading documentation.
gruez 5y ago
>if it's between doing one automated bluetooth test that costs $25 or 5 manual tests which cost $5 each - the 5 tests is clearly a better outcome for society. are we talking about doing 5 tests on the same women, or doing 5 tests on different women?
maxsilver 5y ago
> Any line at all is a positive test. It's not obvious what counts as a "faint line" -- is this too faint? Is it not really there? Am I misreading natural variations in the colour of the test strip? It's not a matter of reading instructions -- even intelligent adults who have followed the directions 100% correctly can still struggle with knowing what counts. Anyone who has ever taken a pregnancy test (or seen someone else take a pregnancy test), can tell you about the major amounts of stress possible attempting to read a "simple faint line" -- see https://www.reddit.com/r/TFABLinePorn/ https://www.reddit.com/r/TFABLinePorn/ for one example. I'm not saying that every test strip needs $20 of Bluetooth gizmos and e-waste. Just that normal, intelligent, fully-instruction-following adults can reasonably be expected to not always know how to read "any faint lines" accurately.
- ethanbond 5y ago
  Not to mention motivated reasoning/perception. Is this positive test going to mean you’re going to cancel your holiday plans and lose thousands of dollars?
- takeda 5y ago
  > It's not obvious what counts as a "faint line" -- is this too faint? Is it not really there? Am I misreading natural variations in the colour of the test strip? If you think of how the test works, then it is obvious that if you can spot the line it is positive.
  - xxpor 5y ago
    I have literally no idea how the test works; I'm a software engineer. They're supposed to be similar to pregnancy tests right? But those detect hormones afaik, not viruses (or antibodies).
    - takeda 5y ago
      The test contains antibodies for the virus, so if they react in any way (assuming you weren't tampering with it[1]) then you have the virus. Those tests are considered unreliable, because the false negative is high (i.e. not enough of the virus to register). I don't know enough about pregnancy test, but I assume the hormone is always present, it's just certain level of it signals pregnancy. [1] there were videos where people where testing juices and soft drinks and that was messing up the test.

elif 5y ago

the machine readers that doctors and hospitals use for test strips are used hundreds of times per day on multiple samples

smnrchrds 5y ago
I am sure reusable machines exist. What I am not sure (really not sure, it may or may not be feasible) is if they can be made at consumer-level price point and with consumer limitations (e.g. no requirement for maintenance or calibration for the lifetime of the device). I imagine the professional devices cost thousands of dollars and undergo regular maintenance.

lm28469 5y ago

> a simple yes/no output has value The line is a boolean indicator. Either it's there or it isn't. People are dumb as rocks but come on, what's the next step ? Shipping a doctor with every test ? We maybe need a bluetooth sensor in masks because apparently people don't know if they should use them above or under their nose.... I'm pretty sure our brains are more than calibrated enough to discern basic shapes and colors. These tests are an insult to our intelligence.

gruez 5y ago
>The line is a boolean indicator. Either it's there or it isn't. No it's not. The world is analog, not digital. The parent comment specifically mentions this: >and not worry about "is that a faint line I am seeing? Do faint lines count?" situation
- lm28469 5y ago
  Have you used these tests ? Have you read their manuals ? Of course the world is analog, it doesn't prevent me from assessing if I have socks on or not, or if my light bulb is on or off ... Faint lines do count, as stated in the documentation, if your eyes can see something it means it's positive, that's all there is to know, these tests have been designed to be used by humans...
  - dragonwriter 5y ago
    > if your eyes can see something This is not a consistent standard from person to person.
  - lazide 5y ago
    Having used the tests multiple times (including the Ellume tests), and having Covid positive and negative results (due to a child getting it twice!! this year)? It is really hard to tell sometimes. And sometimes people don’t want to see a specific answer, and will fight over if something is positive or not. The Binax now faint line for instance can be really faint-but-still positive, and I personally got in an argument with his mom over if it counted as positive or not (day 5 and 5th positive test in a row, with decreasing line clarity each time).

simion314 5y ago

>This makes sense, because you can calibrate the sensor in the factory and not worry about "is that a faint line I am seeing? Do faint lines count?" situation anymore. Converting continuous data to a simple yes/no output has value. But can you trust this calibrations? I bought a infrared thermometer and for some fucking reason for my son always shows at least +1 degrees but is fine for everyone else in the family. I discovered this only after a few days where his fever would not calm down and I found some old thermometers and confirm that is broken(still shows fever for him a month later and I could not find any logical explanation what is special with my son)

rootusrootus 5y ago
AFAIK 1 degree does not count as a fever, especially in children. That's within the range of normal variation.
- simion314 5y ago
  It is always over 38 Celsius which qualifies as fever where under the tongue is 1 degree less. So if I use it on my I get 36.4 on my son I get 38.4 , even if I try different areas of the body is still converges on the high value.
- mc32 5y ago
  I think they’re saying it always seems to be off by one degree for their son compared to other thermometers.
xkcd-sucks 5y ago
Re: IR thermometers, the temperature measurement is related to surface emissivity (basically the fraction of heat that gets radiated as light), which can be pretty variable between people (skin grease, cosmetics, sweat). As well as variability in blood flow etc. if it's a forehead measurement. In the antigen test strip case one would hope the materials and lighting to be controlled, so less risk of miscalibration (even if it's a stupid way to satisfy somebody's demand for a test to be made "quantifiable")