hCG Test: Blood Test vs Home Urine Test

An hCG test checks your urine or blood for hCG, the pregnancy hormone your body starts making soon after a fertilised egg implants in the uterus. A home urine test gives a yes or no answer from about the first day of a missed period. A blood hCG test, which a doctor requests, can pick up lower levels a few days earlier and give an exact number.

Key takeaways

• A home urine test is most reliable from the first day of a missed period; testing earlier can give a false negative.
• A blood test picks up hCG earlier and measures the exact level, which doctors use to follow an early pregnancy.
• One hCG number means little on its own; how it changes over two days tells your doctor more.
• See a doctor after a positive test, and call 000 or go to an emergency department for heavy bleeding or severe pain.

What an hCG Test Measures

An hCG test measures human chorionic gonadotropin, a hormone made by the cells that go on to form the placenta. Results are given in international units per litre (IU/L), and a level under 5 IU/L usually means you're not pregnant. Whether you test your urine at home or have blood work for a pregnancy test, each kind answers a slightly different question.

Doctors use the measured blood test when they need a number, such as after IVF, with bleeding or pain, or when a pregnancy might be ectopic.

hCG Levels in Miscarriage and Ectopic Pregnancy

hCG levels on their own can't diagnose a miscarriage or an ectopic pregnancy, but the way they change over a few days, read alongside an ultrasound, helps a doctor tell. In a healthy early pregnancy the level usually climbs steeply, often doubling every two to three days in the first weeks. A level that falls on repeat tests suggests the pregnancy is ending or has ended in a miscarriage.

A level that rises more slowly than expected, or stays flat, can be a sign of an ectopic pregnancy, where the pregnancy grows outside the uterus, most often in a fallopian tube. A slow rise can also happen in a pregnancy that goes on normally, so your doctor usually repeats the hCG test 48 hours later and arranges a transvaginal ultrasound. Once the level passes a certain point, usually somewhere between 1,500 and 3,500 IU/L, a pregnancy in the uterus should show on that scan.

A pregnancy outside the uterus can't continue safely and needs urgent care. Pain on one side of your lower abdomen, pain in the tip of your shoulder, bleeding, dizziness or fainting in early pregnancy mean calling 000 or going to an emergency department.

Other Causes of a Raised hCG Result

A raised hCG result almost always comes from a pregnancy, but a few other things can cause it. The hormone can take several weeks to clear after a birth, a miscarriage or a termination, or after treatment for an ectopic. Fertility injections that contain hCG can give a positive result for up to about two weeks. A molar pregnancy, where abnormal tissue grows in the uterus instead of a baby, causes very high levels, and rarely some tumours of the ovary, testis or other organs make hCG too. Small amounts can also come from the pituitary gland around menopause.

Tests that detect hCG can't tell where it came from. Very occasionally, antibodies in the blood interfere with a pregnancy blood test and give a falsely raised result; a urine test isn't affected by them, so it helps sort that out. If your result is positive and you're sure you're not pregnant, your doctor can look for the cause.

Two Kinds of hCG Test

The two kinds of hCG test are qualitative, which says yes or no, and quantitative, which measures the exact amount. A qualitative test can use urine or blood and shows only whether hCG is above a set level; home tests are this kind. A quantitative pregnancy blood test, often just called a beta-hCG, gives a number in IU/L and can detect very low levels of the hormone.

Doctors use the quantitative kind for repeat testing: two results about 48 hours apart show whether the level is rising as expected. That matters when a miscarriage is possible or a pregnancy might be ectopic, after fertility treatment, or when a home test and your symptoms don't match. Your doctor arranges it with a pathology request, and the result goes back to them to explain.

Next Steps After a Positive Result

After a positive result, the next step is to see a GP, who can confirm the pregnancy and help you plan what comes next. A positive home urine test is usually accurate, so many people don't need a blood test, but your GP may arrange pregnancy blood work if you've had bleeding or pain, an ectopic in the past, IVF or an unclear result.

Start folic acid (at least 400 micrograms a day, or more if your doctor advises) and iodine (150 micrograms a day, unless your doctor has told you otherwise) if you haven't already, avoid alcohol, and check any regular medicines with your doctor or pharmacist before you stop or change them. Your GP can talk through antenatal care with a hospital, a midwife or an obstetrician, and when to have your first ultrasound, which can detect the heartbeat and date the pregnancy, and the other checks offered in the first trimester. If the pregnancy wasn't planned, they can talk through all your options in confidence.

How to Avoid a False Negative Result

The best way to avoid a false negative result is to wait until at least the first day of your missed period and test your first urine of the morning, when hCG is most concentrated. In early pregnancy the level is still low, so testing too soon, or after drinking a lot of fluid, can leave too little hCG in the sample for the strip to detect.

Follow the instructions for your test exactly, read it at the stated time, and check the use-by date. If the test is negative and your period still hasn't come, test again in two to three days. If it's still negative after a week, or your cycle is often irregular, see your doctor, who can arrange blood work for a pregnancy test, which picks up lower levels.

Blood Pregnancy Test Versus Home Urine Test

A pregnancy test is a check of your urine or blood for hCG, the hormone your body makes once a pregnancy has implanted. You might need one because your period is late, because you have early signs such as tender breasts, nausea or tiredness, or before a medicine, an X-ray or surgery where being pregnant would change the plan.

Comparing a blood test vs home urine test comes down to timing and detail. A home urine test is quick, private and accurate from the first day of a missed period. A blood test needs a doctor's request and a visit to a collection centre, but it picks up a pregnancy a few days earlier and can give an exact level rather than a yes or no.

A beta-hCG pregnancy test is the measured blood test. It looks for the beta part of chorionic gonadotropin, the part that belongs to hCG alone, so other hormones don't interfere with it. Most people need only a home test. A blood test is more useful after IVF, with bleeding or pain, after a past ectopic, or when home results and symptoms don't add up.

When to See a Doctor After a Positive Test

See a doctor in the first few weeks after a positive home pregnancy test, to confirm the pregnancy and start your antenatal care. Go sooner if you have a condition such as diabetes, epilepsy or high blood pressure, take regular medicines, or have had an ectopic or a miscarriage before. In early pregnancy, any bleeding or pain is a reason to see a doctor promptly.

Call 000 or go to an emergency department for heavy bleeding, severe or one-sided pain in your abdomen, pain in the tip of your shoulder, or feeling faint. See a doctor quickly, too, if early pregnancy sickness stops you keeping fluids down, or you pass very little urine or it's very dark, because you may need fluids.

Typical hCG Levels by Week of Pregnancy

Typical hCG levels vary so widely from one pregnancy to the next that a single number tells you little; the trend over a few days matters more. Weeks of pregnancy are counted from the first day of your last period. At 4 weeks of pregnancy the level is often somewhere between 5 and about 400 IU/L, by 5 weeks it can be anywhere from about 20 to over 7,000, and by 6 weeks from about 1,000 to over 50,000.

The level usually peaks at around 8 to 11 weeks of pregnancy and then falls, settling lower for the rest of the pregnancy. Twins tend to give higher numbers, and so does a molar pregnancy. A home test only shows whether hCG is there, so it can't tell you how far along you are; an ultrasound does that better.

Summary

An hCG test confirms a pregnancy, and a blood hCG test also shows how the level changes, which helps doctors check on an early pregnancy and look for problems. If you have a positive or unclear result, a Medio GP can talk it through by phone, request a blood test, and refer you for an ultrasound or antenatal care if they think it's right.

Frequently asked questions

How do I use pregnancy test strips?

Collect your first morning urine in a clean, dry cup, then dip the strip in up to the marked line for the time the instructions give, usually a few seconds. Lay it flat and read it at the stated time, often 3 to 5 minutes. What happens during the test is simple: a control line shows the strip worked, and a second line shows it found hCG.

What is hCG when not pregnant?

When you're not pregnant, hCG is normally under 5 IU/L. A higher level without a pregnancy usually means a recent pregnancy or miscarriage, a fertility injection or, rarely, a molar pregnancy or a tumour. Human chorionic gonadotropin is made by the developing placenta, so the level rises once you're pregnant: hCG levels at four weeks of pregnancy are usually above 5 and often in the tens or hundreds.

Can a doctor help with hCG test?

Yes. A GP can request a pregnancy blood test, explain what the levels mean for you, and arrange repeat testing 48 hours later if the number needs watching. A beta-hCG test is used after fertility treatment, with bleeding or pain in early pregnancy, or when an ectopic pregnancy is possible. Medio's GPs can help by phone, for adults 18 and over.

How much does a beta hCG pregnancy test cost?

A beta hCG blood test that a doctor requests for a clinical reason usually attracts a Medicare rebate, and many collection centres bulk bill it for people with a Medicare card. Without a rebate, the laboratory sets the fee, so ask the collection centre before your test. Home urine tests are sold at pharmacies and supermarkets.

Can too much pee on a pregnancy test make it negative?

Usually not, but flooding the test can spoil it: dipping past the marked line or for too long can make the result unreadable, and the control line may not show. A very diluted sample, from drinking a lot before testing, is the more common cause of a false negative. Pregnancy tests use hCG to detect pregnancy: antibodies on the strip catch the hormone and form the test line.

Is it better to dip or pee on a pregnancy test?

Either works if you follow the instructions for your test. Dipping the strip into urine collected in a clean cup gives you more control over timing, while peeing on a midstream test is quicker. Your hCG levels change quickly during early pregnancy, often doubling every two to three days, so a faint line is worth repeating in a couple of days.