Tuesday, September 13, 2011

Pee on a Stick

Pregnancy tests are not created equal.  Every commercial you see tests that say they can tell five days before your missed period, or tests that come up with a digital answer, or tests that smile at you.  When you go to buy tests, there are so many to choose from, and it is so intimidating.  Do you spend $30 on 6 six tests, or $9 on one test that says "pregnant" or "not pregnant" so you don't have to interpret lines?  Do you choose one that has two lines or one that has a plus sign?  Why are they either pink or blue?

It took me a very long time to realize that each test is very different, even tests that you buy in the same box can respond differently even when taken with the same cup of urine.

I hated feeling so confused about which tests to buy, especially once I started learning more about how each test has a different sensitivity, so I researched.

I couldn't believe the huge difference between each test, and it was more than just what they showed or how they tested.  As most of those that pee on sticks know, it isn't just about looking at the test and then saying if it is positive or negative.  You hold it up to the light, you talk to the stick, you take the strip out of the case and hold it up to the light, you keep it for hours to analyze later.  All you want is that second line or plus sign, and analyzing is what we all do.

Knowing that there are different sensitivities, the level of false positives, and other information about the test can make it easier to put down the test instead of inspecting it for hours on end (though from personal experience, it is still really hard to put the test down and walk away even if you know all about them).

Most of the sensitivity information I got from Pee on a Stick, but I did call the bigger brands and get more information directly from their customer service.  It's amazing how much information they are willing to give about their tests when you ask, and it can really help you choose which test you want to use.

1.  Some general information

Most digital tests always have two lines if you pop open the case and look at the test strip.  Digital tests test the sensitivity of the line, not the fact that there is two lines.  Opening a digital test that says "Not Pregnant" and seeing two lines does not mean you are pregnant.

All pregnancy tests are only valid for 10 minutes once they have been peed on or dipped in or drops put in.  If a positive shows up after the 10 minutes, it means nothing.  A positive needs to show up within the 10 minute time frame.  Have a timer set to 10 minutes, and once it dings, throw the test away.  Resist the urge to pull the test back out later and look for a second line.  It can give you false hope if you see two lines.

Evaporation lines do exist.  Most evaporation lines are not the color of the test (so not pink or blue) but, again, if after the 10 minute time frame, they can be.  Most evaporation lines are gray or look like a shadow, and are NOT a positive test.  The second line needs to be the same color as the test, if it isn't, it isn't a positive result.

There are also evaporating positives on tests, which are rarely talked about but exist.  If you test, see a positive right away, but it disappears before the 10 minutes is up, it is NOT a positive result.  Again, the best way to check for a positive is to check right before 10 minutes is up, if there is a second line the same color as the test without turning it this way and that, it is a positive result.  If not, it's a negative.

Pregnancy tests are not considered accurate until at least twelve days after ovulation.  Yes, people get positive results before then, but that doesn't mean everyone will.  Some test later, some earlier.  If you get a negative result, it does not mean that you aren't pregnant.  If your period doesn't show up, test again.  A lot of people get negative results only to get a positive result a few days later.

First morning urine is the best time to test.  Overnight, you go longer without going to the bathroom, so your urine will have a higher hormone concentration in the morning than any other time of day.  If you are testing early, use your first morning urine.  You will get the most accurate result.

Blue dye tests do have a higher false positive rate than pink dye tests.  For some reason, the blue dye pregnancy tests are not as accurate as pink dye tests.  There are higher instances of false positive results using blue dye, though that number is still pretty low.  To keep that risk at a minimum, try to stick with pink dye pregnancy tests.

Tests that give a +/- result are very likely to have some bleed over into the + area.  Because the test is a crossover test and not two solitary lines, there might be some blue dye in the area of the +.  This does not make it a positive result.  You need the full + for this test to be a positive result, not just a few dots or tiny crossover.

Some women will not respond to some tests, or will not show a positive with a urine test at all.  Some only respond to certain tests, and no one knows why.  There are even some women that will never show positive on urine tests, no matter how pregnant they are.  If you are late for your period (whether charting or not), try a different test if you are still getting a negative result.  If you still get a negative result (especially if you know when you ovulated) you might need to go in for a blood draw.

2.  Sensitivities and Other Information

Key:
+ : Recommended test
- : Not recommended test
+/- : They work for some women, but not all
? : Not enough information to recommend or not
P : Pink Dye
B : Blue dye
Sensitivities are in mIU, a level of 20 mIU on a blood test is when you would be confirmed as pregnant


Test Name
Sensitivity
Recommend
Other Information
AimStep
20
+ P
Used in most doctor's offices
AimStep Midstream
20
+ P
“”
AimStep Stick
20
+ P
“”
AimStep Dip
20
+ P
“”
Answer Quick & Simple Early
25
- P
Disappearing positives are common
New Choice (Dollar Store Test)
25
+ P
Accurate test, not very expensive
Clearblue Digital
25-50
+/- B
False positives reported, known sensitivity of 25, reported at 50
Clearblue Easy
50
+/- B
False positives reported, very light colored test/hard to read
CVS (cassette)
50
? B



CVS (midstream)
25
? B



Early Pregnancy Test
10
+ P
Very accurate early result for most women
Early-Pregnancy-Tests.com
20
+/- P
False positives reported, though not common
EPT (II)
50
+ B
 
EPT (+/-)
25
- B
False positives reported, test can be hard to read even just the control line
EPT Certainty
50
- B
Many false positives
Equate (II)
25
+ P



Equate (+/-)
25
+ P
Control line disappears, but positive result will remain for most women
First Response Early Response
25/12.5
+ P
Many get result with sensitivity as low as 12.5, disappearing positives can occur
Inverness (II)
50
+ B



Inverness (+/-)
25
- B
False positives reported, inaccurate result common
SaveOnTests.com
20
? P



TestsForLess.com
20
? P



Rite Aid
25
- B



Target
25
- B
Very light control line
Walgreen
25
- B



Walgreen Digital
25
+/- B



Wondfo Strips
20
+/- P
These strips work for some, for others false positive readings are very high, as are evaporation lines


Store brand tests are distributed and made by Inverness, and most with the +/- result are not recommended.

Just from this, most of the blue dye tests reported false positives, weak control lines, and hard to read results. Personally, I would stick with any test that uses pink dye.  Your result will be more accurate, with less false positives, easier to read control lines and positive results, and pink is much easier to distinguish from the gray evaporation lines that do happen.

Please remember, tests are NOT accurate after ten minutes, so throw them away.  Any result you receive after the ten minute mark is not a viable result and you will need to retest to find out what the answer truly is.  A lot of blue dye tests, when taken apart, have a very clear positive area where the result would pop up.  If you open the cassette or take pictures and invert the colors, it is very possible you will see something that looks like a positive test.  Please remember that if you can see a positive result on a test from however far away you would read a book, that is a positive test.  Do not hold it up to the light this way and that, don't invert the colors, and don't keep the test after ten minutes have gone by.

A line is a line is a line, but it is very important that you read the test the way it was intended and the understanding of how each test works can save you from heartbreak from having a false result.


I called the major pregnancy test companies to find out any reported issues and their sensitivities.  Everything I found out is listed in the above table.  This is not a medical guide, and this post is not to take the place of medical advice if you are possibly pregnant.  This is just a guide for pregnancy tests, no more.

4 comments:

Danielle said... [Reply to comment]

Great info, Kayce! Looks like you put a lot of work into this post!!

Janine @ Alternative Housewife said... [Reply to comment]

I loved my dollar store test - Got one positive so just took another. Easy peasy. I got a few negatives with that test as well, never any false responses.

Really interesting post!

Crystal - Prenatal Coach said... [Reply to comment]

Wow really comprehensive post! Thanks for the info!

Tabatha Carmichael said... [Reply to comment]
This comment has been removed by the author.

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