Diferencia entre revisiones de «Beta-HCG»
(Comprehensive update: add background, indications, interpretation pearls, causes of elevated hCG; fix chart values (week 3); add 8 peer-reviewed references) |
(Remove 3 refs with incorrect PMIDs (verified against PubMed)) |
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==Background== | ==Background== | ||
*Human chorionic gonadotropin (hCG) is a glycoprotein hormone produced by the syncytiotrophoblast of the placenta | *Human chorionic gonadotropin (hCG) is a glycoprotein hormone produced by the syncytiotrophoblast of the placenta | ||
*Detected in maternal serum as early as 6-8 days after ovulation | *Detected in maternal serum as early as 6-8 days after ovulation | ||
*The beta subunit is specific to hCG and is what is measured by pregnancy tests (''qualitative'' = urine, ''quantitative'' = serum) | *The beta subunit is specific to hCG and is what is measured by pregnancy tests (''qualitative'' = urine, ''quantitative'' = serum) | ||
*In normal early pregnancy, serum hCG approximately doubles every 48-72 hours, peaking at 8-11 weeks of gestation<ref name="barnhart2004" /> | *In normal early pregnancy, serum hCG approximately doubles every 48-72 hours, peaking at 8-11 weeks of gestation<ref name="barnhart2004">Barnhart KT, Sammel MD, Rinaudo PF, et al. Symptomatic patients with an early viable intrauterine pregnancy: HCG curves redefined. Obstet Gynecol. 2004; 104(1):50-55. PMID 15229000.</ref> | ||
==Indications== | ==Indications== | ||
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*Evaluate for [[ectopic pregnancy]] in patients with abdominal pain or [[Vaginal Bleeding Pregnant (less than 20wks)|vaginal bleeding]] | *Evaluate for [[ectopic pregnancy]] in patients with abdominal pain or [[Vaginal Bleeding Pregnant (less than 20wks)|vaginal bleeding]] | ||
*Serial monitoring to assess viability of early pregnancy | *Serial monitoring to assess viability of early pregnancy | ||
*Evaluate for [[ | *Evaluate for [[Molar pregnancy|gestational trophoblastic disease]] (e.g., molar pregnancy) | ||
*Evaluate for possible miscarriage or pregnancy of unknown location | *Evaluate for possible miscarriage or pregnancy of unknown location | ||
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| Postpartum (4-6 wks) || NA || <5 | | Postpartum (4-6 wks) || NA || <5 | ||
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*Values represent approximate ranges and vary by laboratory and assay method<ref name="cole2009"> | *Values represent approximate ranges and vary by laboratory and assay method<ref name="cole2009">Cole LA. New discoveries on the biology and detection of human chorionic gonadotropin. Reprod Biol Endocrinol. 2009; 7:8. PMID 19171054.</ref> | ||
*Wide range of normal values at any given gestational age; a single value should '''not''' be used alone to determine viability | *Wide range of normal values at any given gestational age; a single value should '''not''' be used alone to determine viability | ||
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==Interpretation Pearls== | ==Interpretation Pearls== | ||
*hCG >1,500-3,500 mIU/mL (institutional discriminatory zone) without an intrauterine pregnancy on transvaginal ultrasound should raise suspicion for [[ectopic pregnancy]]<ref name="connolly2013"> | *hCG >1,500-3,500 mIU/mL (institutional discriminatory zone) without an intrauterine pregnancy on transvaginal ultrasound should raise suspicion for [[ectopic pregnancy]]<ref name="connolly2013">Connolly A, Ryan DH, Stuber AR, Postma HJ. Reevaluation of discriminatory and threshold levels for serum beta-hCG in early pregnancy. Obstet Gynecol. 2013; 121(1):65-70. PMID 23262929.</ref> | ||
*Very high hCG levels (>100,000 mIU/mL) should raise concern for [[ | *Very high hCG levels (>100,000 mIU/mL) should raise concern for [[Molar pregnancy|gestational trophoblastic disease]]<ref name="soper2006">Soper JT. Gestational trophoblastic disease. Obstet Gynecol. 2006; 108(1):176-187. PMID 16816073.</ref> | ||
*A ''plateau'' in hCG levels (rise <49% or decline <21% in 48 hrs) is suggestive of a pregnancy of unknown location and may represent ectopic or nonviable intrauterine pregnancy | *A ''plateau'' in hCG levels (rise <49% or decline <21% in 48 hrs) is suggestive of a pregnancy of unknown location and may represent ectopic or nonviable intrauterine pregnancy | ||
*hCG levels may remain detectable for 4-6 weeks after miscarriage or completion of a pregnancy | *hCG levels may remain detectable for 4-6 weeks after miscarriage or completion of a pregnancy | ||
*Heterophilic antibodies can cause false-positive results (hook effect); consider serial dilutions if clinical picture does not match hCG level | *Heterophilic antibodies can cause false-positive results (hook effect); consider serial dilutions if clinical picture does not match hCG level | ||
==Causes of Elevated hCG== | ==Causes of Elevated hCG== | ||
*Intrauterine pregnancy (most common) | *Intrauterine pregnancy (most common) | ||
*[[Ectopic pregnancy]] | *[[Ectopic pregnancy]] | ||
*[[ | *[[Molar pregnancy|Gestational trophoblastic disease (molar pregnancy)]] | ||
*Recent pregnancy loss or termination (residual hCG) | *Recent pregnancy loss or termination (residual hCG) | ||
*Exogenous hCG administration | *Exogenous hCG administration | ||
*Germ cell tumors | *Germ cell tumors | ||
*Peri-menopausal pituitary hCG production (usually low levels <14 mIU/mL) | *Peri-menopausal pituitary hCG production (usually low levels <14 mIU/mL) | ||
==See Also== | ==See Also== | ||
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*[[Maternal Vitals and Labs in Pregnancy]] | *[[Maternal Vitals and Labs in Pregnancy]] | ||
*[[Miscarriage]] | *[[Miscarriage]] | ||
*[[Gestational trophoblastic disease]] | *[[Molar pregnancy|Gestational trophoblastic disease]] | ||
==References== | ==References== | ||
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[[Category:OBGYN]] | [[Category:OBGYN]] | ||
[[Category:Labs]] | |||
Revisión actual - 10:27 22 mar 2026
Background
- Human chorionic gonadotropin (hCG) is a glycoprotein hormone produced by the syncytiotrophoblast of the placenta
- Detected in maternal serum as early as 6-8 days after ovulation
- The beta subunit is specific to hCG and is what is measured by pregnancy tests (qualitative = urine, quantitative = serum)
- In normal early pregnancy, serum hCG approximately doubles every 48-72 hours, peaking at 8-11 weeks of gestation[1]
Indications
- Confirm pregnancy
- Evaluate for ectopic pregnancy in patients with abdominal pain or vaginal bleeding
- Serial monitoring to assess viability of early pregnancy
- Evaluate for gestational trophoblastic disease (e.g., molar pregnancy)
- Evaluate for possible miscarriage or pregnancy of unknown location
Expected Levels by Gestational Age
| Gestational Week | Minimum (mIU/mL) | Maximum (mIU/mL) |
| 3 | 5 | 50 |
| 4 | 5 | 426 |
| 5 | 18 | 7,340 |
| 6 | 1,080 | 56,500 |
| 7-8 | 7,650 | 229,000 |
| 9-12 | 25,700 | 288,000 |
| 13-16 | 13,300 | 254,000 |
| 17-24 | 4,060 | 165,400 |
| 25-40 | 3,640 | 117,000 |
| Postpartum (4-6 wks) | NA | <5 |
- Values represent approximate ranges and vary by laboratory and assay method[2]
- Wide range of normal values at any given gestational age; a single value should not be used alone to determine viability
Repeat Levels
Repeat B-hCG Levels
| Pregnancy Type | B-hCG Change |
| Normal |
|
| Ectopic |
|
| Miscarriage |
|
- A single hCG level cannot reliably distinguish intrauterine from ectopic pregnancy[6]
- The discriminatory zone (typically 1,500-3,500 mIU/mL depending on institution) is the hCG level above which a gestational sac should be visible on transvaginal ultrasound[7]
Interpretation Pearls
- hCG >1,500-3,500 mIU/mL (institutional discriminatory zone) without an intrauterine pregnancy on transvaginal ultrasound should raise suspicion for ectopic pregnancy[7]
- Very high hCG levels (>100,000 mIU/mL) should raise concern for gestational trophoblastic disease[8]
- A plateau in hCG levels (rise <49% or decline <21% in 48 hrs) is suggestive of a pregnancy of unknown location and may represent ectopic or nonviable intrauterine pregnancy
- hCG levels may remain detectable for 4-6 weeks after miscarriage or completion of a pregnancy
- Heterophilic antibodies can cause false-positive results (hook effect); consider serial dilutions if clinical picture does not match hCG level
Causes of Elevated hCG
- Intrauterine pregnancy (most common)
- Ectopic pregnancy
- Gestational trophoblastic disease (molar pregnancy)
- Recent pregnancy loss or termination (residual hCG)
- Exogenous hCG administration
- Germ cell tumors
- Peri-menopausal pituitary hCG production (usually low levels <14 mIU/mL)
See Also
- Pregnancy (main)
- Vaginal Bleeding Pregnant (less than 20wks)
- Ectopic pregnancy
- Maternal Vitals and Labs in Pregnancy
- Miscarriage
- Gestational trophoblastic disease
References
- ↑ 1.0 1.1 Barnhart KT, Sammel MD, Rinaudo PF, et al. Symptomatic patients with an early viable intrauterine pregnancy: HCG curves redefined. Obstet Gynecol. 2004; 104(1):50-55. PMID 15229000.
- ↑ Cole LA. New discoveries on the biology and detection of human chorionic gonadotropin. Reprod Biol Endocrinol. 2009; 7:8. PMID 19171054.
- ↑ Barnhart KT, Guo W, Cary MS, et al. Differences in serum human chorionic gonadotropin rise in early pregnancy by race and value at presentation. Obstet Gynecol. 2016; 128(3):504-511. PMID 27500347.
- ↑ Silva C, Sammel MD, Zhou L, et al. Human chorionic gonadotropin profile for women with ectopic pregnancy. Obstet Gynecol. 2006; 107(3):605-610. PMID 16507930.
- ↑ Doubilet PM, Benson CB, Bourne T, Blaivas M. Diagnostic criteria for nonviable pregnancy early in the first trimester. N Engl J Med. 2013; 369(15):1443-1451. PMID 24106937.
- ↑ Murray H, Baakdah H, Bardell T, Tulandi T. Diagnosis and treatment of ectopic pregnancy. CMAJ. 2005; 173(8):905-912. PMID 16217116.
- ↑ 7.0 7.1 Connolly A, Ryan DH, Stuber AR, Postma HJ. Reevaluation of discriminatory and threshold levels for serum beta-hCG in early pregnancy. Obstet Gynecol. 2013; 121(1):65-70. PMID 23262929.
- ↑ Soper JT. Gestational trophoblastic disease. Obstet Gynecol. 2006; 108(1):176-187. PMID 16816073.