What are the two types of blood tests for pregnancy

Pregnancy Tests

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In this Article

In this Article

A pregnancy test may let you know if you are pregnant.

Here are answers to some of the most common questions about pregnancy tests.

What is a pregnancy test, and how does it work?

Pregnancy tests are designed to tell if your urine or blood contains a hormone called human chorionic gonadotropin (hCG). This hormone is made right after a fertilized egg attaches to the wall of a woman’s uterus.

This usually happens — but not always — about 6 days after fertilization. If you’re pregnant, levels of hCG continue to rise rapidly, doubling every 2 to 3 days.

What types of pregnancy tests are available?

Two main types of pregnancy tests can let you know if you’re pregnant: urine tests and blood tests.

Urine tests can be done at home or in a doctor’s office. Many women first choose a home pregnancy test to take about a week after a missed period. Home pregnancy tests are private and convenient.

These products come with instructions. Follow them closely for the most accurate results. After testing, you can confirm results by seeing your doctor, who can perform even more sensitive pregnancy tests.

Blood tests are done at your doctor’s office, but are used less often than urine tests. These tests can detect pregnancy earlier than a home pregnancy test, or about 6 to 8 days after ovulation. But with these tests, it takes longer to get the results than with a home pregnancy test.

Two types of blood pregnancy tests are available:

A qualitative hCG test simply checks to see if hCG is present. It gives a “yes” or “no” answer to the question, “Are you pregnant?” Doctors often order these tests to confirm pregnancy as early as 10 days after a missed period. Some of these tests can detect hCG much earlier.

A quantitative hCG test (beta hCG) measures the exact amount of hCG in your blood. It can find even very low levels of hCG. Because these pregnancy tests can measure the concentration of hCG, they may be helpful in tracking any problems during pregnancy. They may also (in combination with other tests) be used to rule out a tubal (ectopic) pregnancy or to monitor a woman after a miscarriage when hCG levels fall rapidly.

How accurate are pregnancy tests?

Waiting at least a week after a missed period may give you the most accurate result. Results may also be more accurate if you do the test first thing in the morning, when your urine is more concentrated.

Urine home pregnancy tests are about 99% accurate. Blood tests are even more accurate than this.

How accurate a home pregnancy test is depends upon:

  • How closely you follow instructions.
  • When you ovulate in your cycle and how soon implantation occurs.
  • How soon after pregnancy you take the test.
  • The sensitivity of the pregnancy test.

Is it expensive or hard to do a home pregnancy test (HPT)?

You can buy a home pregnancy test in a drugstore without a prescription. The cost depends on the brand. But most tests are relatively inexpensive — from $8 to $20.

Home pregnancy tests are quick and easy to use. They are also very accurate if you carefully follow directions. These pregnancy tests all work in a similar way. You test the urine in one of these ways:

  • Hold the test’s stick in your urine stream.
  • Collect urine in a cup and then di p the test’s stick into it.
  • Collect urine in a cup and use a dropper to put urine into another container.

With all of these techniques, you need to wait a few minutes before seeing the results. Results may show up as a line, a color, or a symbol such as a “+” or “-” sign. Digital tests produce the words “pregnant” or “not pregnant.”

If you have any questions about the pregnancy test or the results, call your doctor or the telephone number listed with the home pregnancy test.

What do the pregnancy test results mean?

It’s important to know what a positive or negative result means.

If you get a positive result, you are pregnant. This is true no matter how faint the line, color, or sign is. If you get a positive result, you may want to call your doctor to talk about what comes next.

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.

If you get a negative result, you are likely not pregnant. However, you may still be pregnant if:

  • The test is past its expiration date.
  • You took the test the wrong way.
  • You tested too soon.
  • Your urine is too diluted because you drank large amounts of fluids right before the test.
  • You are taking certain medications, such as diuretics or antihistamines.

If you get a negative pregnancy test result, try retesting within about a week to double-check. Some home pregnancy tests suggest doing this regardless of your results.

What if you get two different results? Call your doctor. A blood test is a good idea to confirm results.

American Pregnancy Association: “Understanding Pregnancy Tests: Urine & Blood.”

American Pregnancy Association: “Taking a Pregnancy Test.”

American Pregnancy Association: “Pregnancy FAQ: Early Pregnancy.”

Department of Health and Human Services: “Pregnancy Tests: FAQs.”

Pregnancy Test

These days it is very easy to test at home whether you are pregnant or not by using home pregnancy test kits. All pregnancy tests work by detecting a certain hormone in the urine or blood that is only there when a woman is pregnant. This hormone is called human chorionic gonadotropin hCG. It is also called the pregnancy hormone.

hCG is made when a fertilized egg implants in the uterus. This usually happens about six days after the egg and sperm merge. But studies show that in up to 10 percent of women, implantation does not occur until much later, after the first day of the missed period. The amount of hCG rapidly builds up in your body with each passing day you are pregnant.

Home pregnancy tests detect hCG in your urine if you are pregnant. You can either buy a kit and do it yourself, or visit a health professional to have a test done.

Are there different types of pregnancy tests?

Yes. There are two types of pregnancy tests. One tests the blood for the pregnancy hormone, hCG. You need to see a doctor to have a blood test. The other checks the urine for the hCG hormone. You can do a urine test at a doctor’s office or at home with a home pregnancy test (HPT).

These days, many women first use an HPT to find out if they are pregnant. HPTs are inexpensive, private, and easy to use. HPTs also are highly accurate if used correctly and at the right time. HPTs will be able to tell if you’re pregnant about one week after a missed period.

Doctors use two types of blood tests to check for pregnancy. Blood tests can pick up hCG earlier in a pregnancy than urine tests can. Blood tests can tell if you are pregnant about six to eight days after you ovulate (or release an egg from an ovary).

A quantitative blood test (or the beta hCG test) measures the exact amount of hCG in your blood. So it can find even tiny amounts of hCG. This makes it very accurate. A qualitative hCG blood test just checks to see if the pregnancy hormone is present or not. So this test gives a yes or no answer. The qualitative hCG blood test is about as accurate as a urine test.

How does a home pregnancy test work?

Home pregnancy tests have absorbent sticks or cards that test your urine. There are two main types of test kit – one which is a stick that you hold in your urine flow whilst sitting on the toilet (this is called a midstream urine test), or one where you collect some urine in a small container and then dip the tester in.

The tester detects human chorionic gonadotrophin (hCG – a hormone of pregnancy) in your urine if you are pregnant. When a woman becomes pregnant the placenta will start producing hCG within 6 – 10 days of conception. The level of this hormone increases rapidly, doubling every 1 to 2 days until it peaks after about 10 to 12 weeks.

Most kits need you to hold the stick in the urine for 5 – 10 seconds, and will give you the result within one to two minutes.Once the time has passed, you should inspect the “result window.” If a line or plus symbol appears, you are pregnant. It does not matter how faint the line is. A line, whether bold or faint, means the result is positive. New digital tests show the words “pregnant” or “not pregnant.”

Most tests also have a “control indicator” in the result window. This line or symbol shows whether the test is working properly. If the control indicator does not appear, the test is not working properly. You should not rely on any results from a HPT that may be faulty.

Most brands tell users to repeat the test in a few days, no matter what the results. One negative result (especially soon after a missed period) does not always mean you’re not pregnant. All HPTs come with written instructions. Most tests also have toll-free phone numbers to call in case of questions about use or results.

How early can I test to see whether I am pregnant?

Most home pregnancy test kits can be used from the day that your period is due. Some tests, however, can detect a pregnancy starting from 4 days before your period is due.

Each kit can detect different levels of hCG in your urine – most commonly the kits begin detecting hCG at 25 mIu/mL. A few kits can detect hCG as low as 15 mIu/mL and is effective from up to four days before your period is due.

The levels of hCG in your urine are highest first thing in the morning when you go to the toilet after waking up. However, the modern test kits are now so sensitive that they are able to detect hCG at any time of the day. Just remember not to drink lots of fluid before taking the test – this will dilute the amount of hCG in your urine.

Remember that a negative test does not always mean that you are not pregnant – you may just have conducted the test too early, i.e. before there was enough hCG in your urine. If your period does not arrive within the next 7 days, repeat the test – it is for this reason that tests are often purchased as packs of two.

A positive test, however, is 99% accurate (but be aware that a false positive could be caused by a recent miscarriage or fertility drugs).

Home Pregnancy Test Results

When you use a pregnancy test kit there are a variety of results that you can get. Here’s an overview of the various possibilities:

Negative pregnancy test result

The test is telling you that you are not pregnant. If you are pretty sure you are pregnant due to the symptoms you are experiencing, then it is possible that you have got a false negative pregnancy test result

False negative pregnancy test result

This occurs when you are pregnant, but your hCG levels are still too low to be detected by the test. It is best to take the test again in a few days to a week’s time.

Positive pregnancy test result

The test kit is telling you that you are pregnant. You may be feeling confused by this result – for instance, you may have had what you thought was your period (but was actually spotting or an implantation bleed) and you are actually pregnant.

Or, the test kit may be wrong.

False positive pregnancy result

There are occasions when you may get a false positive result – these include times when you have had a recent miscarriage and there is still hCG in your blood, or when you have recently been on fertility drugs.

If you are really worried and your symptoms don’t seem to match your test results, then you can go to a health professional, and have a blood test done.

How Soon Do Pregnancy Tests Work

Pregnancy tests are designed to tell you if you are pregnant based on a sample of your urine or blood, depending on the type of test that you’re using. There are a lot of different models to choose between, and most of them offer very accurate results. When it comes to choosing a trustworthy test, we recommend that you don’t cheap out as higher priced models tend to deliver a higher accuracy, being more dependable. But let’s not waste time on generalities anymore and let’s research more about these useful tests.

Types of tests

There are two types of tests out there, more precisely urine and blood tests. In the following, we will take a closer look at both types so that you may better understand how they work.

Urine tests

Urine pregnancy tests, like Clearblue, are the most commonly used as they provide a fast answer and they can even be used at home. This home test is convenient as it doesn’t cost a lot of money and it is 100% private as you do it by yourself, not needing anyone else’s help. All of these tests come with instructions that you have to follow closely for the results to be accurate. Unfortunately, the downside to urine tests is the fact that they aren’t the most reliable. Therefore, it’s best to repeat the test 1-2 days later again or go to the doctor’s office in case the results are contradictory or you want to be 100% sure about the response.

Blood tests

There are two types of blood tests that you can turn to, more precisely qualitative hCG tests and quantitative hCG tests. The downside to blood tests is the fact that they are done only in the doctor’s office. On the other hand, their accuracy is more increased, so even if there’s the inconvenience of having to make an appointment and see the doctor to take the test, thus your privacy being invaded in case you didn’t want anyone else to know about the pregnancy’s possibility, it’s best that you turn to it in order to receive a clear response.

Signs that you should take the test

The signs that you’re pregnant are pretty similar with the signs that your period is coming for most women, especially for those who have problems with their period because it never comes on time. To better understand what are the signs of a potential pregnancy in order to know whether it’s a good idea to take the test or not, read the following lines.

Your period is delayed

The first sign of pregnancy is a missed or a delayed period. However, there are a lot of women who have problems with their periods, meaning that it usually doesn’t come on time. In case you don’t have a regular menstrual cycle, you should take the test if more than a month passes since your last period. Also, don’t be fooled by light bleeding. In case you suspect that you might be pregnant and you experience light bleeding, it’s recommended that you take the test to find out for sure whether you’re pregnant or not. If the test turns out positive and you are bleeding, go to your doctor’s office as soon as you can for further investigations as issues with the pregnancy might exist.

Your breasts are swollen and they hurt

As soon as you get knocked up, your body produces more progesterone and estrogen. These are the hormones that help produce changes in your body, mainly in the way that your breasts look and feel. One of the most obvious signs that you should check whether you’re pregnant or not is when your breasts become swollen, appearing bigger, and when they feel tender to the touch. Other signs include the fact that your nipples with be sensitive and that the veins will look a bit darker.

You’re experiencing uncomfortable cramps

Another sign that you should take a test, a sign that it common for pregnancy as well as menstruation is the appearance of cramps. If you feel a slight discomfort and a few days pass but your period doesn’t come, take the test to be sure if these are menstrual cramps or pregnancy cramps.

How early can you take the test?

Now that you know more about pregnancy tests, it’s time to find out the answer to the question that’s on your mind, more precisely how soon will the tests work. The answer depends on the type of test that you’re going with. In case you perform a urine test with a product such as First Response, you have to take it a week after the missed period. If you go with a blood test, you can take it six to eight days after the ovulation period. On the downside, although blood tests can be performed quicker, it takes longer to find out the results. Basically, no matter the type of test that you go with, you will find out the answer quick, no matter if you go with a urine test that shows the result after a couple of minutes and that you use seven days after the missed period, or if you choose the blood test that you can perform as soon as six days after the ovulation but that gives you the results a bit later.

Blood Pregnancy Test

You are now several days post ovulation and you suspect that this might be the cycle that you conceived! The next question that you might ask yourself is: should I run to the doctor for a blood pregnancy test or should I take a home pregnancy test?

Like most questions related to fertility and pregnancy, there is no straightforward answer to this question. Both a blood pregnancy test and a home pregnancy test will identify the presence of the pregnancy hormone called human chorionic gonadotropin (hCG), and will determine if you are pregnant or not. So, to determine which test is right for you, you might want to consider convenience, expense, accuracy, and your fertility history.

There are actually two different types of blood pregnancy tests, also called pregnancy serum tests. One type, called a quantitative blood pregnancy test (or a beta hCG test), measures the exact amount of hCG in the blood, while a qualitative blood pregnancy test simply provides confirmation of the presence of hCG, and a “yes” or “no” answer for pregnancy. If the blood pregnancy test reveals that hCG is under 5 mIU/ml, then the test will be considered negative. If the level of hCG is determined to be between 5 and 25 mIU/ml, this is said to be an equivocal result, and another test should be performed in a few days to confirm pregnancy.

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As for home pregnancy tests, there are several types to choose from. All home pregnancy tests (HPT) detect the presence of hCG in urine, and come either in a test strip, midstream or digital format. With the test strip or midstream format, you will dip the strip in a urine sample or urinate directly on the stick, wait a few minutes, and watch for the appearance of a colored test line to appear, which indicates a positive result. A digital test will typically provide a definitive “no” or “yes” in words that appear on the digital display. Each unique HPT is calibrated to detect a specific level of hCG in the urine, such as 20 mIU/ml, 50 mIU/ml or 100 mIU/ml. More “sensitive” tests, those that are able to detect a lower amount of hCG, can provide an accurate result as early as 7-10 days post ovulation.

When deciding if you should use an HPT or have a blood pregnancy test done at the lab, here are a few items to consider:

  • Convenience: While it is true that a quantitative blood test can confirm pregnancy a couple of days before an early detection HPT, a qualitative blood test that is set to detect 25 mIU/ml is no more sensitive than an early detection HPT. Many women find it more convenient to simply wait a day or two and take a pregnancy test in the privacy of their home. In addition, an HPT will typically produce results in just minutes. On the other hand, you might be on pins and needles for up to 48 hours while you wait for results from a blood pregnancy test.
  • Expense: The out of pocket expense for a blood pregnancy test will vary depending on the clinic you choose and the type of insurance you have. You should expect to pay up to about $75 for this service. And, if the results are uncertain (hCG level between 5 mIU/ml and 25 mIU/ml), a retest will be required in a few days, which will in most cases incur an additional fee. On the other hand, you can purchase 10 early detection pregnancy test strips for about $10, which will allow you to test several days in a row if necessary.
  • Accuracy: The most “accurate” pregnancy test is the quantitative blood pregnancy test, as it determines the exact amount of hCG in your blood. This will allow your doctor to make a very clear determination about whether or not you are pregnant or if a retest is required in a few more days. With both a qualitative blood test and an HPT it is possible to get a false negative result. This means that if the test is not sensitive enough to detect your current level of hCG (for example, your current level is 20 mIU and the test is set to detect hCG at 25 mIU), you will get a negative test result even though you are pregnant. If you get a negative result from an HPT or a qualitative blood test, and you continue to have any signs of pregnancy, we recommend retesting in a few days.
  • Fertility history: If you have experienced a miscarriage or an ectopic pregnancy in the past, your doctor may well want to monitor your hCG levels closely in the first several weeks of pregnancy. In the early days of pregnancy, hCG levels double every 48-72 hours. (See the chart below for average blood hCG levels as pregnancy advances). If hCG levels do not rise appropriately in those very early days, it can signal a problem with the pregnancy. By monitoring your exact hCG levels with regular quantitative blood test, your doctor may be able to detect a problem early on. Neither a qualitative blood test nor an HPT allows this type of monitoring, as they do not reveal exact amounts of hCG, and cannot determine if levels are increasing appropriately.

The following is a list of blood hCG levels achieved as pregnancy advances (LMP means last menstrual period):

  • 3 weeks since LMP: 5 – 50 mIU/ml
  • 4 weeks since LMP: 5 – 426 mIU/ml
  • 5 weeks since LMP: 18 – 7,340 mIU/ml
  • 6 weeks since LMP: 1,080 – 56,500 mIU/ml
  • 7 – 8 weeks since LMP: 7,650 – 229,000 mIU/ml
  • 9 – 12 weeks since LMP: 25,700 – 288,000 mIU/ml
  • 13 – 16 weeks since LMP: 13,300 – 254,000 mIU/ml
  • 17 – 24 weeks since LMP: 4,060 – 165,400 mIU/ml
  • 25 – 40 weeks since LMP: 3,640 – 117,000 mIU/ml

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По материалам:

http://www.webmd.com/baby/guide/pregnancy-tests

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