A Complete Guide to Pregnancy Tests

While trying to conceive, pregnancy tests become a pretty big part of your life! And as you might have noticed, there are a TON of choices out there.

So how do you know which one is best? Does more expensive necessarily mean more accurate? What about blue dye pregnancy tests vs. pink dye pregnancy tests?

And there are a lot more questions where those came from! Like, when to take your pregnancy test, how they work, reading pregnancy test results – the list goes on and on.

After seeing so many pregnancy-test-related questions in my inbox every week over on Instagram, it only made sense to put together a complete guide for you!

I *think* we hit on everything here, so you’ve got your total testing resource at the ready. All right mama – let’s talk pregnancy tests!

If you haven’t already, please feel free to join over 400k new moms and follow me here on Instagram for awesome pregnancy + birth tips!

What is a home pregnancy test?

In short, a home pregnancy test looks for the presence of hCG – human chorionic gonadotropin – a hormone produced during pregnancy.

Home pregnancy tests usually involve peeing on a test strip or dipping a test strip into your urine to detect for the presence of hCG. This can be indicated in various ways depending on the type of test used (more on this in a minute!).

Production of hCG begins around 6-8 days after implantation. This is why some women receive positive pregnancy tests well before their missed period. However, when they are used the day after your expected period, they are considered over 99% accurate.

In other words – home pregnancy tests work!

Types of pregnancy tests

So now that you understand what we’re testing for, let’s get into the different types of home pregnancy tests. There are so many out there, and if you’ve spent any time on a pregnancy or TTC forum, then you know that everyone has an opinion on which is best!

The truth is home pregnancy tests are almost all created equal. Seriously! They have very similar sensitivity levels and can detect hCG levels between 20-35 mIU/ml.

I think where the trouble lies is when you start testing for pregnancy before your missed period. You see, as the days until your missed period decrease, your likelihood of an early positive pregnancy test increase. This is because the hormone hCG roughly doubles in your body every two days. The more that is being produced, the higher chance of it triggering a positive test – makes sense, right?!

Some websites and brands will provide charts that compare sensitivities but keep in mind that these levels are being reported by the companies themselves and are not checked for accuracy.

With all of that being said, let’s still take a look at the different options out there.

Blue dye vs. pink dye pregnancy tests

Okay, so this is always a big topic of discussion and debate that I see in the TTC communities out there. So, home pregnancy tests generally show results with dye or digitally. A positive result on a dye test is usually indicated by a line or plus sign, that is activated by a chemical reaction.

Dye tests use either pink dye or blue dye, and unofficially (but anecdotally) moms seem to like pink dye much better! This is because the pink dye is less likely to show an evaporation line, which can be read as a false positive (we’ll get into this a bit more below!).

Dye tests come in a variety of forms, ranging from simple strips that you dip into urine, to easy to maneuver sticks that you can put directly into your urine stream.

First Response is always a popular pink dye option, but if you are someone that likes to test a lot in the days leading up to your expected period, cheap test strips are the way to go!

Cheapie pregnancy tests

These inexpensive home pregnancy tests, known on the TTC forums as “cheapie pregnancy tests” are a super popular and economic option. They are no-fluff, pink dye test strips, that you dip into your urine. And the Easy@Home Pregnancy Urine Test Strips claim a sensitivity as low as 25 mIU/ml.

Two lines mean you’re pregnant and one line means you are not pregnant. And at less than $10 for 20 tests, this is a must for people who like to test frequently!

Digital home pregnancy tests

Now that we talked all about the dye test options, let’s talk about digital home pregnancy tests. These tests work on the same principle – measuring the presence of hCG. Hands down the most popular on the market are the Clearblue Digital Pregnancy Teststhe 5 pack is the way to go here 😊

In fact, inside of the digital pregnancy test, there is an hCG test strip! But in addition, there is a little computer board that basically reads the test results for you. Based on what it reads, it is programmed to digitally display a word or result. Usually, this is “pregnant” or “not pregnant”.

Naturally, digital tests are popular because they take away any guesswork to reading your results. You’re not left debating if there really *is* a faint line or not. And for many, this is exactly the peace of mind they need!

Pregnancy test with weeks indicator

Another type of digital pregnancy test is one with a weeks indicator. This type of test will confirm your pregnancy and estimates how many weeks it’s been since conception. It seems that it will tell you if it’s been 1-2 weeks since conception, 2-3 weeks since conception, or 3+ weeks since conception.

After doing quite a bit of digging at the time of publishing this article – it seems that this type of pregnancy test is not currently available in the US. I did however find that Clear Blue UK and Clear Blue Canada have their digital pregnancy test with weeks indicator on the market.

So perhaps it is coming to the US soon!

Blood pregnancy test

Okay, so the topic of this article is mostly focusing on home pregnancy tests, but I didn’t want to leave this out. A pregnancy blood test is done in a healthcare setting and is able to detect a much smaller amount of hCG than a urine test.

Pregnancy blood tests are often used to confirm a urine pregnancy test or to check for pregnancy well before your expected period. This type of pregnancy test can also be used to track hCG levels over time (which can help determine viability).

Some other reasons your provider might order a blood pregnancy test are: if you’re receiving fertility treatments, have risk factors for a high-risk pregnancy, or to track a pregnancy with multiples early on.

Related: What is Non-Viable Pregnancy

DIY Pregnancy Tests

All right, and to wrap up this list of types of pregnancy tests I can’t leave out the DIY pregnancy tests. I actually have a whole article dedicated to DIY pregnancy tests for you to check out!

But the idea is that some common household items can have a reaction to hCG and indicate pregnancy. Some of the most popular ones involve vinegar, toothpaste, and the Tylenol and hydrogen peroxide test.

In short, these DIY options are not considered a reliable predictor of pregnancy and shouldn’t be used to substitute for a store-bought pregnancy test. However, I like to recommend them as a fun activity once you already know you’re pregnant. Then you can see if the results hold up!

When to take a pregnancy test?

Whew. So now that you know your options when it comes to testing, what about the timing? As you know, pregnancy tests are over 99% accurate if you wait until the day after your expected period. So ideally, you should take a pregnancy test the day after your missed period.

But girl, I know that it can be really hard to wait that long! Especially with so many tests on the market claiming results up to 5 days before your missed period.

But I want you to remember that hCG production doesn’t begin until after implantation…so what does that mean for your positive result?

Let’s back up a bit for a little biology lesson

As you know, when you are trying to conceive, it becomes important to understand your cycle and learn how to track ovulation. This is because throughout any given cycle you have a fertile window of about 5 days. The days leading up to ovulation are when you want to try to get pregnant and hope the sperm meets the egg.

Once this occurs, the fertilized egg will take a few days to make its way towards the lining of your uterus for implantation. There is a wide range of normal here, but most sources say it takes anywhere from 3-7 days.

Well, it isn’t until your egg implants that the hormone hCG production begins. This is the hormone that will be largely responsible for many first-trimester pregnancy symptoms, and what will trigger your positive pregnancy test.

In other words, it’s impossible for a pregnancy test to be positive until implantation occurs, which is 3 to 7 days past ovulation. And for some women that can take up to 12 days. And then the hCG needs to rise high enough to meet the threshold for a positive test.

So, when should I test?

I recommend trying your hardest to wait until your expected period, but if you want to test sooner, don’t go more than 3 days early! Testing earlier than that *may* give you a positive – it’s certainly not impossible – but most likely it’s just going to lead to needing to test again if and when you do miss your period.

I know that’s easier said than done, so if you already know you’re gonna test frequently, get a big pack of these home pregnancy test strips, mama!

Best time of day to take a pregnancy test?

But along with timing when to take the test in terms of ovulation and your missed period, you also have to think about the time of day!

The short answer is to test first thing in the morning! The concentration of hCG will be highest then, and if you are testing earlier than your missed period, that’s especially important! Once your expected period has passed, it’s less important to test with the first pee of the day, but it’s still definitely best practice.

Pregnancy test results

Moving right along, let’s talk about the results of your pregnancy test. I’ve already touched on this but pregnancy tests are very accurate. If you see a positive result – you are almost certainly pregnant!

No matter how faint the positive result is, if you can see it, it means hCG was detected. What’s important to note is that it only counts if it is within the testing window in the instructions.

Most tests say that results need to be read within 5-10 minutes of testing for accuracy. This is mostly because of the phenomenon known as evaporation lines.

Evaporation line on pregnancy test

An evaporation line is a faint, colorless line that can show up in the pregnancy test window as the test dries out. Sometimes, women see this line and think it’s a positive result, but it is just a dreaded evaporation line.

As long as you stick to the instructions and read the results before the test dries out, you won’t be fooled by an evaporation line. Many women say that evaporation lines are more prominent on blue dye tests, and this is why pink dye tests are often preferred.

False negative pregnancy test

The most common reason for a false negative pregnancy test is an irregular cycle. Above, I reviewed the timeline of a typical cycle, but if you ovulated much later than the average, or implantation occurred later than expected, false negatives can happen.

Basically, an abnormal timeline could mean that your hCG levels wouldn’t be high enough to trigger a positive pregnancy test even on or the day after your missed period. The biggest clue that this happened would be if you miss your period AND have a negative pregnancy test.

If this occurs, wait two days and then test again. Remember, hCG levels double roughly every 2 days, so by following that pattern you should catch a positive pregnancy test within 7-10 days of your missed period.  And, it should go without saying that if you have any concerns you can always call your provider!

False positive pregnancy test

In very rare cases, you can have a false-positive result. This means you’re not pregnant, but the test says you are!

You could have a false-positive result if blood or protein is present in your urine. And certain drugs, such as tranquilizers, anti-convulsants, or hypnotics may also cause false-positive results.

Again, this is extremely rare.  If your pregnancy test showed a positive, it’s pretty safe to start celebrating, preparing, and getting educated about what to do next right away.

The two week wait

Well, mama, if you’re here I can reasonably guess that you are trying to conceive or suspect you might be pregnant. So many of us want to know as soon as possible if this was our month and enduring the dreaded two-week wait can feel like an eternity!

I thought I’d give you a few tips to make the two-week wait a little less terrible:

  • Stay away from message boards and forums
  • Don’t get too caught up in symptom spotting
  • Keep yourself busy with a fun project or great book
  • Share your journey with a trusted female friend so you have someone to talk things through with other than your partner

Other TTC and early pregnancy resources

I want to wrap up this article by pointing you towards some other helpful articles here at MLN that can help you during this time in your life:

Have a good pregnancy test story? Drop it in the comments below to share with the community!

Liesel Teen, BSN-RN
Founder, Mommy Labor Nurse

Meet Liesel Teen

Hi there. I’m Liesel!

As a labor and delivery nurse, I’ve spent countless hours with women who felt anxious — even fearful — about giving birth. I want you to know it doesn’t have to be that way for you!

When you know what to expect and have the tools to navigate the experience, you’ll feel confident and in control.

I believe you deserve a better birth — no matter how you deliver.