Pregnancy test blood vs urine

When To Take, Types & Accuracy

Overview

How Does a Pregnancy Test Work?

What is a pregnancy test?

A pregnancy test is a way to determine if you’re pregnant. If your pregnancy test is positive, it means you’re pregnant. If the test is negative, it means you aren’t pregnant. Pregnancy tests work by detecting human chorionic gonadotropin (HCG), a hormone your body makes when you’re pregnant.

From the very beginning of pregnancy, your body starts to go through changes to support the cells that will develop into your baby. One thing that happens very quickly is the production of HCG. If you’re pregnant, your body starts to produce more HCG. Your HCG levels start to build up once the fertilized egg implants in your uterus — about six to 10 days after conception.

There are two main types of pregnancy tests — urine tests and blood tests. Often, you’ll take a urine test at home with a home pregnancy test. This type of test is available over the counter (you don’t need a prescription from your healthcare provider) and in a variety of price ranges. Blood tests to check for pregnancy happen in your healthcare provider’s office and involve giving a sample of your blood. The other way to confirm a pregnancy is by using an ultrasound. Your provider performs an ultrasound in their office.

There are several reasons why you might take a pregnancy test. You could be trying to get pregnant and hoping for a positive result. You might have experienced an issue with your birth control. You might even be about to have a medical procedure or start a new medication that could be complicated by pregnancy. No matter what the reason, if you ever have any questions about your test results, the best thing to do is reach out to your healthcare provider.

What hormone levels are checked for a pregnancy test?

Pregnancy tests look for an elevated amount of HCG. Levels of HCG rise quickly – doubling every few days in the first weeks of pregnancy. The placenta produces HCG. Only pregnant people have a placenta, which develops shortly after a fertilized egg attaches to your uterine wall.

When should I take a pregnancy test?

If you think you could be pregnant, it’s a good idea to take a test and make sure. Home pregnancy tests can differ in how early they’ll detect a pregnancy. In many cases, you might get a positive result from an at-home test as early as 10 days after conception. For a more accurate result, wait until after you’ve missed your period to take a test. Remember, if you take a test too soon, it could be negative even if you’re pregnant. If you get a negative test and then miss your period, take another test.

What time should I take a pregnancy test?

In general, the best time is when you have your first morning pee. However, some pregnancy tests are sensitive enough to detect HCG no matter what time of day you take the test. When possible, try to wait until it’s been three hours since your last pee before you take the test. You could also take two pregnancy tests to confirm you get the same result.

Test Details

How do pregnancy tests work?

When you take a pregnancy test, it’s looking for the amount of human chorionic gonadotropin (HCG) in your body. You can find HCG in your pee or blood. HCG needs time to build up in your body. Each day of early pregnancy, your body will create more HCG. As the weeks go on, you’ll have more and more HCG in your body, which will make it more likely that a pregnancy test will show as positive. This means if you take a test too soon, it will come back negative.

Pregnancy tests work by reacting to the amount of HCG in either your pee or blood. In a urine test, a piece of reactive paper detects the HCG. This test might show a plus sign, double vertical lines or even the word “pregnant.” Different tests will show a positive result in unique ways. Read the directions that come with the test to know what a positive result will look like. For example, most tests have a control window that shows up first. Seeing a symbol in this window will tell you that the test is working. Keep in mind that different brands of tests will take different amounts of time to show a result.

If you take a blood test, your provider will take a sample of your blood and send it to a lab. The lab will determine the amount of HCG in your blood. Your provider will contact you with your results.

What are the different types of pregnancy tests?

There are two main types of pregnancy tests: urine and blood tests.

Urine tests are typically done at home — though you can have a urine test done at your healthcare provider’s office — while your provider performs a blood test.

At-home pregnancy test

An at-home test uses your pee to look for HCG. They contain special strips that detect HCG. Most at-home pregnancy tests are about 99% effective when used correctly. That’s about the same accuracy rate as pregnancy tests done in your healthcare provider’s office. These tests are available in most drug or grocery stores. They’re easy to use and inexpensive. It’s important to read the instructions on these tests before taking them.

There are three ways to take an at-home pregnancy test:

Pee in a clean cup. Then, place one to several drops of your pee on a chemical strip.
Place the pregnancy test strip in your urine stream while you pee.
Pee in a clean cup and then dip the test strip in the pee while it’s still in the cup.

For many of these tests, HCG can be detected in your urine about 10 days after conception. However, taking it after you miss your period reduces the chance of getting a false-negative result. A missed period typically happens around 14 days after conception.

There are a few things to keep in mind when you take a home pregnancy test, including:

Use your first morning pee if you can. This is the time of day when your HCG levels will be the most concentrated and easily detected. If you do it at another time of day, try to make sure your pee has been in your bladder for at least three hours.
Don’t drink excessive amounts of fluids before you take a pregnancy test. This can dilute (thin out) your HCG levels.
Check the expiration date on the package.
Read the directions that come with the test thoroughly before starting the test, and follow every step exactly.

Blood test

Another type of pregnancy test is a blood test. Blood tests are rarely done because they’re expensive and tend to have the same result as a urine test. This type of pregnancy test is done using a small sample of blood from a vein in your arm. This blood test not only detects whether the pregnancy hormone is in your body, but can also determine how much of the hormone is present. This is helpful for when your provider needs to know the exact amount of HCG in your blood, not just if there’s HCG in your blood.

A blood test for pregnancy might be done in special circumstances, such as for people who are having fertility treatments or when the healthcare provider thinks there might be a problem.

These blood tests are slightly more sensitive than urine tests because they can detect very small levels of HCG. That means they can provide a more accurate answer very early on in pregnancy — within seven to 10 days after conception. For this test, your blood sample is taken at your provider’s office or the hospital, then sent to a lab for analysis. Results might take anywhere from a few hours to two days.

Your provider might also choose to use a blood test to compare HCG levels during the pregnancy. Your HCG levels usually double about every two days during the first few weeks of pregnancy. If the levels don’t rise, it might suggest a problem with the pregnancy. Extremely high HCG levels might mean that you’re carrying twins or that there’s an issue with the pregnancy.

Are all home pregnancy testing methods the same?

Most brands of at-home pregnancy tests are reliable. Although the exact testing method of different pregnancy tests can differ from one type to the other, they all look for HCG in your body. If you’re using an at-home test, most will give you the same result. The difference with your at-home tests will be the sensitivity of the test. Some might be more sensitive than others and produce a positive result (detect HCG in your urine) sooner than others. For the most accurate reading, it’s still recommended that you wait until you’ve missed your period. At that point, all tests should be accurate.

What are the advantages of using a home pregnancy test?

There are quite a few advantages to using a home pregnancy test, including:

Pregnancy tests are inexpensive.
They’re easy to use.
Home tests provide results quickly.

According to pregnancy kit manufacturers, most at-home pregnancy tests are 98% to 99% accurate when you use them exactly as instructed. Positive results can be trusted, but you can get a false negative result if you take the test too soon.

Blood tests tend to be more expensive and inconvenient. However, blood tests can detect pregnancy sooner and are the only tests to show specific amounts of HCG in your body.

Is there anything you shouldn’t do before a pregnancy test?

Most pregnancy tests don’t ask you to avoid activities or change your lifestyle. The only medication that may interfere with your results is fertility medication containing HCG.

Here are some helpful tips you should follow for the best results:

Read the instructions carefully before doing anything.
Wait until you miss your period to take the test.
Use your first pee or pee from a full bladder. Chugging water before your test in order to pee may affect your results.

Results and Follow-Up

How long does it take to get results of a pregnancy test?

Each home pregnancy test is different. Read the instruction manual carefully. It will tell you how many minutes to wait for your result. In most cases, you can expect to wait three minutes for your result. Keep in mind that if you wait too long to check your result, it may be inaccurate.

Even a faint line on a pregnancy test could mean you’re pregnant. Your test will also have a control window that indicates that you took the test correctly. The instructions with your test will outline all of this. If you have any questions or remain unsure of your result after several tests, please contact your healthcare provider.

A faint line is different than an evaporation line. An evaporation line may appear if you wait too long to check your results — meaning your pee is dry. Most tests ask you to read your results before 10 minutes. This ensures the pee doesn’t dry up and you don’t get an evaporation line.

How soon will a pregnancy test be positive?

It depends on which type of test you use. Some at-home pregnancy tests may be able to detect pregnancy before you miss your period. However, if you want the most accurate result, it’s best to wait until you have missed your period.

How accurate are pregnancy tests?

Pregnancy tests are about 99% accurate when you use them correctly.

How common are false results on pregnancy tests?

False results — either a false negative or a false positive — mainly happen due to using the test incorrectly. The main reason for a false-negative is testing too early. You might also get a false-negative if you use a home test incorrectly, such as using too much or too little pee. It’s important to follow the directions on your test kit to make sure you get an accurate result.

Can a positive test be wrong?

A false positive is rare, but it can happen. This may be the case if you experience a chemical pregnancy or lose the pregnancy shortly after the fertilized egg attaches to your uterine wall.

What type of pregnancy test confirms pregnancy first?

A blood test confirms pregnancy first because it can detect a smaller amount of HCG as compared to a test that uses your pee.

Are there any medications that can change the result of my pregnancy test?

For the most part, medications don’t change your pregnancy test results. Antibiotics, pain relievers and alcohol don’t impact your test results.

However, fertility drugs are one exception. These medications can sometimes cause a false-positive on your pregnancy test. If you’re taking fertility medications, reach out to your healthcare provider about your results to make sure they’re accurate.

What should I do after getting a positive pregnancy test?

If you take a pregnancy test at home and it’s positive, there are a few things you should do, including:

Take your prenatal vitamins. Pick a vitamin with folic acid included in the ingredient list. Start taking these while you’re trying to conceive, if possible. This is because the folic acid can help prevent complications during fetal development.
Call your healthcare provider for an appointment. This appointment might not happen for several weeks — but it’s a good idea to call your provider and make an appointment.
Make sure to pursue healthy habits like not drinking alcohol or smoking during pregnancy. You may also want to limit the amount of caffeine you consume each day during pregnancy.

Additional Details

Will an ectopic pregnancy show up on a pregnancy test?

Yes, you’ll still have a positive result on a pregnancy test if you have an ectopic pregnancy.

A note from Cleveland Clinic

Pregnancy tests are how a person finds out if they’re pregnant. Most people take a pregnancy test at home using their pee. However, you can also take a pregnancy test at your provider’s office using a blood sample or pee. For the most accurate results, wait until you miss your period to take a home pregnancy test. If you use pregnancy tests correctly, the results are 99% accurate. Contact your healthcare provider if you have questions about the results of your pregnancy test.

Urine pregnancy Tests Vs. Blood Pregnancy Tests

We provide both urine pregnancy tests and blood pregnancy tests in our office. Before you come in, we want you to know what to expect if you think you may be pregnant. Both tests detect the presence of a hormone called Human Chorionic Gonadotropin (hCG). The placenta produces this hormone quickly after the embryo attaches to the uterine lining and builds up rapidly in your body in the first few days of pregnancy.

When is a Urine Pregnancy test done?
Urine Pregnancy tests can be performed in our clinic. Most doctors recommend that you wait until the first day of your missed period before taking a urine pregnancy test. Urine tests or home pregnancy tests are around 97% accurate when done correctly. However, if done incorrectly and especially if taken too early, the result can be inaccurate. This test is done in our clinic by the patient simply providing our trained medical staff with a urine sample. The staff member will then use a Urine dipstick that detects the hCG pregnancy hormone to determine if you are pregnant or not. The results are seen within a few minutes, two lines indicating a positive pregnancy test and one line indicating a negative pregnancy test.This is a very simple and effective way to detect pregnancy. In this test, there are antibodies present on the strip which become sensitive if the hCG hormone is present in the urine sample.

We also preform blood pregnancy tests in our clinic.
This is done by one of our trained medical staff members drawing a small amount of your blood via venipuncture.

What to expect during the blood draw?
Well, no one looks forward to getting their blood drawn, however, this procedure is usually brief and uneventful without complications. Most people are through with the entire procedure in under 15 minutes. The procedure begins by the phlebotomist gently pressing his or her fingers against your skin to locate the best and most accessible vein. Then she will put on gloves, and clean the skin area with an alcohol pad. Next they will tie a tourniquet around your upper arm to increase blood flow, ask you to make a fist, and insert the needle to begin the blood draw. After blood is retrieved, your blood will then be labeled immediately and sent off to a lab for testing. The detection of hCG hormone in one’s blood sample confirms pregnancy. We typically do a qualitative blood hCG test just to confirm pregnancy. This test is more accurate than the urine pregnancy test as it gives a quantitative result. We like to say that the urine pregnancy test can lie, the blood pregnancy test doesn’t.

A more detailed test called a quantitative hCG test if not typically performed unless there is a need. In this test, the concentration of the hCG hormone corresponding to the days of gestation (pregnancy) is detected and accurately known. The levels of beta hCG gets doubled so long as the pregnancy is progressing normally. If the levels start to decrease, in repeated tests, it indicates a possible loss of the embryo. A high level of the hCG hormone in early pregnancy may mean a multiple fetus pregnancy, which you are not able to tell by a urine test. This test is also useful for the doctors to rule out ectopic pregnancy. This is a condition where pregnancy grows outside the uterine cavity. If the level of hCG fails to rise in subsequent tests a risk of ectopic pregnancy is suspected. These are the substantial differences between a blood and urine pregnancy test.

what shows the norm during pregnancy, how and when to take, decoding

June 2, 2020

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Contents

What is HCG?

The role of the hormone in the diagnosis of pregnancy

When should I donate blood for hCG?

How to prepare for the analysis? nine0003

HCG test interpretation

How accurate is the hCG test?

An hCG blood test is one of the most important tools for monitoring a developing pregnancy.

What is HCG?

An hCG blood test is a reliable way to determine pregnancy in the early stages. HCG is a protein consisting of two units. Alpha particles of the hormone are similar to biologically active substances secreted by the pituitary gland. Beta particles are unique. The mass of the CG molecule is approximately 46 kDa. During pregnancy, glycoprotein is synthesized in the placenta. The biological properties of CG are in many ways similar to the properties of other hormones: luteinizing and follicle-stimulating. In some malignant diseases, hCG begins to produce tumor cells. In a non-pregnant woman and a healthy man, the hormone is practically absent in blood tests. nine0003

In obstetrics and gynecology, the test for b hCG, along with ultrasound, is used to monitor pregnancy throughout the entire period. Deviations in the readings of the analysis are the basis for further examination and require the consultation of a geneticist. An artificial increase in the level of hCG is used in the IVF process. As a result of injections of hCG in women, the maturation and release of the egg is stimulated, the production of estrogen and progesterone increases. In men, the introduction of exogenous hCG activates the growth of the number of spermatozoa. nine0003

It is proved that the substance also has the properties of corticotropic hormone. HCG has an effect on the adrenal glands, stimulating the synthesis of steroids in their cortex. Thus, he is involved in preparing the body of a pregnant woman for the upcoming physiological stress. Since the fetus is perceived as foreign by the mother's body, some immunosuppressive influence of hormones, including hCG, is required for its normal development.

HCG promotes the maturation of placental tissues. Thanks to him and other hormones, its functional activity increases and the number of chorionic villi increases. nine0003

Without the hormone, the normal development of the embryo is not possible. HCG ensures the production of estrogens and progesterone, and also maintains their balance in the body of the expectant mother. Therefore, any pregnancy support program always contains regular tests for hCG levels.

Urinalysis for hCG (beta particles)

Compared to blood, expectant mother's urine contains less of the hormone. Therefore, determining the concentration of a substance in the urine can diagnose pregnancy only from a period of 8-10 days. Like a laboratory study, pharmacy tests are also based on the determination of hCG in the urine. Home tests have a lower threshold of sensitivity than laboratory tests, and, accordingly, a lower degree of reliability. Their positive result requires a visit to an obstetrician-gynecologist to confirm a normal pregnancy. nine0003

Free hCG assay (beta-hCG subunit)

The range of application of this test is quite wide. In oncology, it is in demand as a marker of malignant tumors. Measurement of the number of independent particles of hCG in the blood is informative in relation to testicular cancer in men. In addition, this indicator is important in the diagnosis of trophoblastic tumors in women. It is included in 1 and 2 pregnancy screenings. The study helps to assess the risk of such congenital fetal pathologies as Down syndrome and Edwards syndrome. nine0003

The role of the hormone in the diagnosis of pregnancy

An analysis of the amount of total hCG occupies a special place in confirming pregnancy in the early stages. This is due to the fact that the hormone begins to be actively released already a few days after the attachment of the fetal egg to the wall of the uterus. With the normal development of the embryo, the level of the substance doubles every 1.5-2 days. By the tenth week, the amount of hCG in a woman's tests can reach maximum values - up to 225,000 mU / ml. nine0003

Simultaneously with the blood for total hCG, other examinations are prescribed for the pregnant woman. So the patient should visit the ultrasound scanning room at least three times. Within nine months, several studies may be required. Comprehensive screenings of the 1st and 2nd trimesters also include an hCG test.

When to donate blood for hCG

A blood test for the hormone is given as needed. The hCG test is prescribed for the first time directly during the diagnosis of pregnancy itself. The second is as part of screening with ultrasound and other tests. Screening is designed to identify a risk group for congenital fetal pathologies among pregnant women. nine0003

Approximate dates of studies on hCG:

confirmation of pregnancy - from the 6th day after conception;
first - from 11 to 13 weeks;
second from 19 to 23 weeks;
3rd trimester screening is done after 28 weeks of gestation.

How to prepare for a blood test

Preparing for an hCG test involves a number of standard requirements for hormone testing. The analysis is given on an empty stomach, after an overnight fast in the morning or afternoon. You should come to the treatment room in good health. In order for the results of the hCG test to be as reliable as possible, it is recommended in 2-3 days: nine0003

stop drinking alcohol;
exclude spicy and fatty foods from the diet;
cancel strength training;
Avoid smoking a couple of hours before donating blood.

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What is a pregnancy test and how does it work - blog of ON Clinic medical center

The question of pregnancy planning has always been relevant in the life of every woman. In the past, confirmation of the fact of motherhood was carried out 2-3 months after fertilization. Modern tests make it possible to confirm or deny pregnancy after 7-10 days. nine0003

What is a pregnancy test and how does it work?

Pregnancy tests detect the presence of human chorionic gonadotropin (hCG) in a woman's urine or blood. This hormone begins to be actively produced by the membranes of the embryo 6-8 days after fertilization. It is during these periods that the egg penetrates the walls of the uterus. In a non-pregnant woman, the normal level of the hormone is below 5 mIU / ml and the tests do not respond to it. As soon as a woman begins to bear a future fetus, the concentration of the substance begins to increase sharply, to which the tests respond with a positive result. nine0003

What types of pregnancy tests are available?

There are 2 main types of pregnancy tests: urine and blood tests. Urinalysis is the most practical and convenient, since it can be performed at home. In the pharmacy chain and on the shelves of supermarkets, you can see a wide variety of testers of different price categories. They differ among themselves in the level of sensitivity to hCG.

The more expensive ones respond to relatively low levels of hormone increase (10 mIU / ml), and, therefore, allow you to clarify the fact of motherhood at an earlier date - 7 days after conception (5 days before the delay). A positive result from cheaper testers should be expected from 1-3 days of delay in menstruation, when the concentration of the hormone in the urine will be at least 25 mIU / ml. nine0003

Pregnancy tests also differ in how they are used:

test strips. They are the most popular option to use. They are impregnated with special reagents that perceive hCG. They must be lowered into a container with urine to a certain mark and wait a few seconds. The result should be expected after 5 minutes, but not later than 10;
jet tests. For its implementation, there is no need to collect urine. It is enough to hold it under a stream of urine for a few seconds and wait for the result; nine0061
tablet test. This option is a strip placed in a plastic tablet with two windows. In one of them, a small amount of urine is placed using a pipette. In the next window, the result will be visible in a few minutes;
electronic test. It is the most accurate of all the previous ones. The principle of its operation is similar, but the result is displayed on the screen.

Is it difficult to take a pregnancy test at home?

Testing at home is not difficult. It can be purchased at any pharmacy without a prescription or in a supermarket. In addition to being affordable, the tests are highly accurate. The main task in their implementation is to strictly adhere to the instructions. The correct result should be expected after the time interval indicated in the instructions. A result that appeared earlier or later than the specified time is not correct. If a woman has doubts about the reliability of the result, then it is better to contact a gynecologist. nine0003

How accurate are pregnancy tests?

Home tests do not give a full guarantee of obtaining a reliable result, errors sometimes happen. In order to achieve more accurate data and minimize possible errors, the following rules must be observed:

Pregnancy tests should preferably be carried out in the morning, since the greatest amount of the hormone is concentrated in the urine during the night;
the test must not be exposed to dirt or moisture before the urinalysis;
it is unacceptable to use the test after the expiration date;
foreign matter must not enter the urine specimen;
test kit should be stored between 2 and 28°C;
when performing the test, you must strictly follow the instructions.

HCG blood test

In addition to home tests, doctors recommend taking a blood test. It is more informative, since the concentration of the hormone in the blood is several times higher than in the urine. The study allows you to detect pregnancy earlier than urine tests, but it takes more time to complete. nine0003

There are 2 main types of hCG blood test:

qualitative. Answers the question: is the level of the hormone elevated or not, which indirectly suggests the presence or absence of pregnancy in a woman;
quantitative (beta hCG). This analysis reflects the exact concentration of a substance in the blood, so that the doctor can control hormonal changes in dynamics.

To obtain correct blood test results, the following rules must be observed:

the analysis is performed strictly on an empty stomach in the morning;
12 hours before the test, alcohol intake, physical activity, smoking should be completely excluded;
water is allowed on the morning of the test;
all medications should be avoided. If this is not possible, the laboratory and the physician should be notified.

Determining pregnancy is not the only task of a hCG blood test. As noted earlier, during the formation and development of the embryo, the level of the hormone in the woman's body should gradually increase - up to 12-13 weeks of pregnancy. If, with regular monitoring, an increase in the hCG indicator is not observed or the hormone level does not correspond to the generally accepted standard values for a specific period, then this may indicate the development of a missed or ectopic pregnancy, a high probability of miscarriage. nine0003

At a later date, the quantitative determination of hCG can be used as a screening for genetic disorders in the fetus (Down or Edwards syndrome). An important role is also played by the determination of beta-hCG. If a woman has an elevated level of this hormone, and no other characteristic signs of pregnancy are observed, tumor diseases should be suspected.

What do pregnancy test results mean?

If the test is positive, it is more likely that the woman is pregnant. Unfortunately, not always a positive response to a blood or urine test indicates a pregnancy. Such an analysis result is referred to as a false positive. In this case, it is extremely important to find the reason that led to such changes in indicators. It can occur in the following diseases and situations:

hormone-producing tumors - choriocarcinorma, hydatidiform mole;
Dysfunctional pathologies of the ovaries;
ectopic pregnancy;
after spontaneous miscarriage or abortion;
a woman taking tranquilizers, anticonvulsants, and medicines containing hCG;
if there is protein or blood in the urine.

If a woman gets a negative test result, she is most likely not pregnant. However, there are situations when the test can "deceive" and in fact the woman is pregnant. This result of the study is called a false negative. It is more common than false positive and the reasons for its appearance lie in the following:

test expired;
the test was performed too early and its sensitivity is not enough to detect an increase in the level of hCG;
instructions not followed;
the woman had drunk a large amount of liquid before the diagnosis, which caused the urine to become more dilute;
insufficient amount of hCG is excreted in the urine due to impaired renal function;
for pathologies of the cardiovascular system;
the woman is taking diuretics or antihistamines.

A negative result is not a complete proof of the absence of pregnancy. In this case, it is recommended to repeat the test again. It should be noted that the diagnostic capabilities of a blood and urine test for pregnancy should not be overestimated. Their implementation is only one of the diagnostic stages of establishing the fact of pregnancy. The tests do not provide information about the location of the pregnancy. And as already known, the level of the hormone in the ectopic location of the embryo also increases. nine0003

In order to clarify the localization of pregnancy and, in general, about its presence and normal course, doctors definitely recommend an ultrasound scan. Ultrasound of the uterus and its appendages does not require complex preparation. To perform an ultrasound with a vaginal probe, empty the bladder, and when using a surface probe, drink 2-3 glasses of non-carbonated water an hour before the examination.

Regardless of the results of the research, you should not draw independent conclusions and conclusions. You should always consult your doctor for any questions. A thorough examination by a gynecologist will make a comprehensive assessment of the woman's health status and the presence of pregnancy. nine0003

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