Guides
Beta HCG Levels: Negative, Positive and the 48-Hour Rise
In most laboratories, a beta HCG of 5 mIU/mL or below is negative. A single value does not show the week of pregnancy; the 48-hour change and ultrasound are decisive.
Translated from the Turkish original by DoktorClub. The Turkish version is the reference text; this English translation has not been separately reviewed by a physician. Read the Turkish original.
Key takeaway
If blood beta HCG is 5 mIU/mL or below, it is negative in example laboratory ranges. Values such as 0.1 or 1.2 indicate that there is no detectable pregnancy at that time. If your period is still late, the test is repeated a few days later, because it may have been done too early. According to the ACOG 2018 guideline, a single measurement does not show the location or health of the pregnancy; the week of pregnancy is determined by the last menstrual period and ultrasound. Interpretation is always based on the laboratory range on your report.
Short Answer
If blood beta HCG is 5 mIU/mL or below, it is negative in example laboratory ranges. Values such as 0.1 or 1.2 indicate that there is no detectable pregnancy at that time. If your period is still late, the test is repeated a few days later, because it may have been done too early. According to the ACOG 2018 guideline, a single measurement does not show the location or health of the pregnancy; the week of pregnancy is determined by the last menstrual period and ultrasound. Interpretation is always based on the laboratory range on your report.
How does it appear on your report?
This test may appear under different names on laboratory reports:
- Beta HCG (Serum/Plasma): The blood test most often ordered for pregnancy.
- Total HCG: An HCG measurement coded separately from Beta HCG in the national unit list.
- Beta HCG (Urine): A urine pregnancy test performed in the laboratory.
- Free beta HCG: A separate test in the national list, reported in µg/L. Do not confuse it with the beta HCG used to diagnose pregnancy.
In the Test Measurement Units list of the Turkish Ministry of Health, the unit for Beta HCG is IU/L. Many reports use mIU/mL. The number is the same in both units: 1 mIU/mL equals 1 IU/L.
The "My Lab Tests" (Tahlillerim) screen in e-Nabız (Türkiye's national health record app) lists results together with their reference values. Out-of-range results are shown in color. With the chart icon, you can also see how the same test has changed over time. This chart is useful when comparing two beta HCG results. A colored flag alone does not mean a disease. In pregnancy, beta HCG naturally rises above the range given for non-pregnant people.
Normal value and reference range
In a non-pregnant person, beta HCG is very low. Laboratories set their negative and positive cutoffs according to their own methods. The values below are examples.
| Status | Example value (mIU/mL) | Source |
|---|---|---|
| Negative | 5 and below | UW Medicine laboratory |
| Indeterminate zone | 6–24 (repeat recommended after 72–96 hours) | UW Medicine laboratory |
| Positive | 25 and above | UW Medicine laboratory |
| Non-pregnant woman | Below 3 | University of Iowa laboratory |
| Perimenopausal and postmenopausal, not pregnant | Can be up to 8 | University of Iowa laboratory |
A reference range covers 95% of healthy people; about 1 in 20 healthy people may fall slightly outside the range.
Why can't the week of pregnancy be calculated from beta HCG?
Among women in the same week of pregnancy, beta HCG is spread over a very wide range. Below is an excerpt from the University of Iowa laboratory's table. This table cannot be used to calculate the week. It only shows how much the ranges overlap between weeks.
| Week of pregnancy | 5–95% range (mIU/mL) |
|---|---|
| 4 | 10–750 |
| 5 | 217–7,138 |
| 6 | 158–31,795 |
| 7 | 3,697–163,563 |
Source: University of Iowa Health Care, HCG – Serum, Quantitative. For example, a value of 5,000 mIU/mL falls within the ranges for weeks 5, 6 and 7 at the same time. This is why the "calculate the week from beta HCG" tables on the internet are misleading. According to ACOG, beta HCG plateaus at around 100,000 mIU/mL at about week 10. According to the ACOG 2018 guideline, it is the correctly calculated gestational age, not the absolute HCG value, that determines when a normal pregnancy will be visible on ultrasound. The Antenatal Care Management Guideline also recommends using ultrasound reports if the last menstrual period is unknown.
How is the 48-hour change read?
In early pregnancy, the key information comes not from a single value but from the change between two measurements. ACOG recommends that, when an abnormal pregnancy is suspected, the second measurement be taken 2 days later. NICE NG126 also asks for the two measurements to be taken as close to 48 hours apart as possible.
- The minimum expected rise depends on the starting value. According to ACOG and the PERİDER-TJOD 2025 guideline, this rate is 49% if the starting value is below 1,500 mIU/mL. If the starting value is between 1,500 and 3,000 it is 40%, and above 3,000 it is 33%.
- Example: If the first value is 1,000 mIU/mL, it is expected to be above approximately 1,490 after 48 hours.
- Not every healthy pregnancy doubles. According to ACOG, 99% of normal intrauterine pregnancies rise above this minimum threshold. So a rise that falls short of doubling can also be normal.
- NICE NG126 criteria: A rise of more than 63% in 48 hours suggests a developing intrauterine pregnancy. A fall of more than 50% indicates that the pregnancy is unlikely to continue. For changes in between, clinical assessment within 24 hours is recommended.
- A normal rise does not rule out ectopic pregnancy. ACOG and NICE are clear on this. Symptoms always come before numbers.
- A falling value also needs attention. According to ACOG, in about 95% of spontaneous miscarriages the value falls by 21–35% in 2 days. An ectopic pregnancy, however, can rupture even while the value is falling or very low.
What does a high value mean?
The most common cause is pregnancy. Possible explanations for a value higher than expected for the duration of pregnancy are:
- Error in dating: Ovulation may have occurred earlier than expected. This is why gestational age is clarified by ultrasound.
- Multiple pregnancy: According to ACOG, in multiple pregnancies such as twins, beta HCG is higher than in singleton pregnancies of the same week.
- Recently ended pregnancy: The hormone does not drop to zero immediately after a miscarriage. NICE recommends a home urine pregnancy test 3 weeks after a miscarriage.
- Molar pregnancy: The PERİDER-TJOD guideline lists this in the differential diagnosis of first-trimester bleeding. The diagnosis is made by ultrasound.
- Non-pregnancy causes: In some people, heterophile antibodies can give a false-positive result. Some tumors can also produce HCG. For an unexpectedly high value, the laboratory recommends confirming the result with a urine test.
What does a low value mean?
- 5 mIU/mL and below: In example laboratory ranges, there is no pregnancy. If the test was done too early and your period is still late, it is repeated.
- Indeterminate zone: The UW Medicine laboratory recommends a repeat after 72–96 hours for results between 6 and 24 mIU/mL.
- Positive but low for the week: The pregnancy may be more recent than expected. A non-developing pregnancy or an ectopic pregnancy is also possible. According to ACOG, this distinction cannot be made with a single measurement; serial measurements and ultrasound are needed.
When read together
- Beta HCG + transvaginal ultrasound: According to PERİDER-TJOD 2025, the commonly accepted level for seeing the gestational sac is 1,500–2,000 mIU/mL. ACOG, however, recommends a cautiously high value such as 3,500 mIU/mL if this threshold is to be used.
- Positive beta HCG + no sac in the uterus: This picture is called a "pregnancy of unknown location." According to NICE, the possibility of ectopic pregnancy is kept in mind until the location is established.
- Beta HCG + progesterone: NICE NG126 recommends not using progesterone to determine the viability or location of the pregnancy while serial beta HCG is being monitored. Details are in the Progesterone Level article.
- Negative beta HCG + missed period: According to TEMD 2025, the most common cause of absent periods is pregnancy. Once pregnancy is ruled out, tests such as FSH, LH, prolactin and TSH follow.
Preparing for the test
- Biotin: High-dose biotin supplements can interfere with immunoassays. The University of Iowa laboratory states that more than 5 mg of biotin in the last 12 hours may make beta HCG appear falsely low. The Total Testing Process Guideline recommends waiting at least 8 hours for those taking 5–10 mg per day. Tell the laboratory about your supplement before giving blood.
- Hemolysis: According to the Total Testing Process Guideline, a hemolyzed blood sample can affect beta HCG measurement. In that case the laboratory may ask for a new sample.
- Intense exercise: Intense physical activity in the 12 hours before giving blood can affect many hormones, including HCG.
- Same laboratory: Negative cutoffs vary from laboratory to laboratory. If you will compare two measurements, use the same laboratory if possible.
Which doctor, which test?
- Obstetrics and Gynecology: The specialty to see for the first assessment after a positive test.
- Second beta HCG after 48 hours: Ordered to see the trend in early pregnancy.
- Transvaginal ultrasound: Shows the location and week of the pregnancy. According to ACOG, the gestational sac and yolk sac should be visible between weeks 5 and 6.
- First prenatal visit: The Antenatal Care Management Guideline asks for the first visit to take place in the first 14 weeks of pregnancy. At this visit, a complete blood count, blood group, HBsAg, syphilis, TSH and urine tests are checked. An HIV test is also done with the pregnant woman's consent.
- Early check-up if there is risk: ACOG recommends that women with significant risk factors be evaluated for ectopic pregnancy even without symptoms.
In Türkiye
- National guideline: The Perinatal Medicine and High-Risk Pregnancies Society (PERİDER) and TJOD (Turkish Society of Obstetrics and Gynecology) published a joint threatened miscarriage guideline in 2025. The guideline describes monitoring beta HCG 48 hours apart and states that a rise of more than 50% favors an intrauterine pregnancy.
- Data gap: According to the same guideline, there is no comprehensive epidemiological study showing the frequency of threatened miscarriage in Türkiye.
- Prenatal monitoring: The Ministry guideline aims for every pregnant woman to receive at least 4 quality prenatal visits. The first visit takes place in the first 14 weeks.
- Unit standard: In the Ministry's national list, Beta HCG is reported in IU/L. Total HCG and free beta HCG are separate tests.
- e-Nabız: You can see your results with their reference values and compare them with previous measurements on a chart.
When should you seek emergency care?
- If you have severe abdominal or groin pain with a positive pregnancy test, go to the emergency department immediately.
- If a positive test is accompanied by shoulder-tip pain, dizziness, feeling faint or a rapid pulse, call 112 (the emergency number in Türkiye). NICE lists these among the symptoms of ectopic pregnancy.
- Seek emergency care for heavy vaginal bleeding or bleeding with clots.
- Go to the emergency department if your pain is increasing, even if beta HCG is falling. An ectopic pregnancy can rupture even at low values.
- If a positive test is accompanied by abdominal or groin pain, even if mild, see an obstetrician-gynecologist or go to the emergency department the same day.
- If the laboratory or your doctor has called you about your result, call back the same day.
- If your pregnancy test is positive while you have an IUD (intrauterine device) in place, get examined the same day. According to ACOG, up to 53% of pregnancies that occur with an IUD in place are ectopic.
- If you have had an ectopic pregnancy before, make an appointment without delay after a positive test.
Related tests
- Lab Test Guide: all tests
- Progesterone Level: In Ovulation and Pregnancy
- Ovulation Test and LH
- FSH and LH Levels
- High Prolactin
- Estradiol (E2) Levels
What changed? (October 2026)
- New page: based on the June 2026 current text of the NICE NG126 guideline and the PERİDER-TJOD 2025 threatened miscarriage guideline.
- The 48-hour rise thresholds are consistent with ACOG Practice Bulletin 193 (2018); the "calculate the week from beta HCG" approach was deliberately not used.
Sources
- Demir SC, Polat İ, Şahin D et al. PERİDER-TJOD düşük tehdidi ve tedavisi kılavuzu. Turk J Obstet Gynecol 2025;22:96-105. https://doi.org/10.4274/tjod.galenos.2025.36926 (accessed October 2, 2026)
- T.C. Sağlık Bakanlığı Halk Sağlığı Genel Müdürlüğü. Doğum Öncesi Bakım Yönetim Rehberi. 2018, Publication No. 925. https://platform.who.int/docs/default-source/mca-documents/policy-documents/guideline/TUR-MN-21-01-GUIDELINE-2018-tur-Antenatal-Care-Management-Guidelines.pdf (accessed October 2, 2026)
- T.C. Sağlık Bakanlığı SHGM. Tıbbi Biyokimya Toplam Test Süreci Rehberi. May 2024, Publication No. 1287. https://dosyamerkez.saglik.gov.tr/Eklenti/48692/0/tibbi-biyokimya-toplam-test-sureci-rehberipdf.pdf (accessed October 2, 2026)
- T.C. Sağlık Bakanlığı SHGM. Test Ölçüm Birimleri, Versiyon 2. 15.09.2021. https://dosyamerkez.saglik.gov.tr/Eklenti/41467/0/test-olcum-birimleri-versiyon-2-pdfpdf.pdf (accessed October 2, 2026)
- Türkiye Endokrinoloji ve Metabolizma Derneği (TEMD). Adrenal ve Gonadal Hastalıklar Kılavuzu. 2025. https://file.temd.org.tr/Uploads/publications/guides/documents/AdrenalKilavuz2025.pdf (accessed October 2, 2026)
- T.C. Sağlık Bakanlığı. e-Nabız Kullanım Kılavuzu V2.1. 2025. https://enabiz.gov.tr/document/User_Manual.pdf (accessed October 2, 2026)
- American College of Obstetricians and Gynecologists. Practice Bulletin No. 193: Tubal Ectopic Pregnancy. Obstet Gynecol 2018;131:e91-e103. https://doi.org/10.1097/AOG.0000000000002560 (accessed October 2, 2026)
- NICE. Ectopic pregnancy and miscarriage: diagnosis and initial management (NG126). 2019, last updated June 17, 2026. https://www.nice.org.uk/guidance/ng126 (accessed October 2, 2026)
- University of Iowa Health Care. Pathology Laboratory Handbook: HCG – Serum, Quantitative. Current version. https://www.healthcare.uiowa.edu/path_handbook/handbook/test446.html (accessed October 2, 2026)
- UW Medicine Laboratory Medicine. Pregnancy (HCG), Serum. Current version. https://testguide.labmed.uw.edu/view/PG (accessed October 2, 2026)
Frequently asked questions
My beta HCG came back 1.20. Am I pregnant?
No, this value is negative in example laboratory ranges. In these ranges, 5 mIU/mL and below is considered negative. If your period is still late, the test may have been done too early. Repeat it in a few days or consult your doctor.
How many weeks pregnant am I based on my beta HCG value?
The week of pregnancy cannot be calculated from beta HCG. Among pregnant women in the same week, values can differ more than 10-fold. The week of pregnancy is determined by the last menstrual period and ultrasound.
If beta HCG does not double in 48 hours, does it mean a miscarriage?
No, not always. According to ACOG, when the starting value is below 1,500 mIU/mL, the minimum expected rise is 49%. A slower rise or a fall is evaluated by a doctor together with ultrasound.
What does it mean if my beta HCG shows up red in e-Nabız?
The colored flag in e-Nabız (Türkiye's national health record app) shows that the result is outside the range given for non-pregnant people. This is expected in pregnancy. What matters is whether the value fits the duration of pregnancy and its 48-hour change.
Beta HCG is positive but there is no sac on ultrasound. What could it be?
The pregnancy may still be too early to be seen. A miscarriage or ectopic pregnancy can also cause this picture. In this situation, NICE recommends two measurements 48 hours apart and close monitoring of symptoms. If you have pain or feel faint, go to the emergency department without delay.
