on Human Chorionic on Human Chorionic Gonadotropin (HCG) Gonadotropin (HCG)

87KE4 team3

PBL HOMEWORK of OB/GYN

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I.I. What is HCG?What is HCG?

II.II. How to test HCG?How to test HCG?

III.III. What is the clinical significance of What is the clinical significance of HCG detection?HCG detection?

IV.IV. Home pregnancy tests (HPTs)Home pregnancy tests (HPTs)

I.I. HCGHCG

1.hCG is glycoprotein hormone 1.hCG is glycoprotein hormone produced by normal trophoblast produced by normal trophoblast cells(cells( 合体滋养细胞）合体滋养细胞） of the placenta of the placenta during pregnancy. during pregnancy.

2.hCG production starts just a few 2.hCG production starts just a few days after conceptiondays after conception （受孕）（受孕） , , before implantation in the uterus. before implantation in the uterus.

hCG enters the maternal circulation hCG enters the maternal circulation almost immediately after almost immediately after implantationimplantation ， ， about day 21 of the about day 21 of the menstrual cycle. menstrual cycle.

3.hCG is composed of two subunits, al3.hCG is composed of two subunits, alpha and betapha and beta

4.The alpha-subunit is identical to 4.The alpha-subunit is identical to that of the pituitary glycoprotein that of the pituitary glycoprotein hormones: hormones:

lutenizing hormone (hLH), lutenizing hormone (hLH), follicle stimulating hormone (hFSH) follicle stimulating hormone (hFSH) thyroid stimulating hormone (hTSH). thyroid stimulating hormone (hTSH).

5.The ß-subunits of the glycoprotein 5.The ß-subunits of the glycoprotein hormones are unique, giving them hormones are unique, giving them their different biological their different biological characteristics.characteristics.

6.physical function:6.physical function: 1) 1) 作用于月经黄体，增加甾体激素的分泌，作用于月经黄体，增加甾体激素的分泌，

以维持妊娠以维持妊娠 ２）有促卵泡成熟活性，促甲状腺活性，２）有促卵泡成熟活性，促甲状腺活性，

促睾丸间质活性促睾丸间质活性 ３）与尿促性素合用能诱发排卵３）与尿促性素合用能诱发排卵 ４）激素屏障：抑制淋巴细胞活性４）激素屏障：抑制淋巴细胞活性

ⅡⅡ.How to test HCG?.How to test HCG?

１１ .A qualitative urine or blood hCG .A qualitative urine or blood hCG test is ordered as early as 10 days test is ordered as early as 10 days after a missed menstrual period if a after a missed menstrual period if a woman wishes to confirm whether or woman wishes to confirm whether or not she is pregnant not she is pregnant

2.Affecting factors2.Affecting factors 1)Tests performed too early1)Tests performed too early 2) a false negative result in very dilute 2) a false negative result in very dilute

urine. Patients should not drink large urine. Patients should not drink large amounts of fluid before collecting a urine amounts of fluid before collecting a urine sample for a pregnancy test. sample for a pregnancy test.

3)drugs: 3)drugs: （（ 11 ）） diuretics and diuretics and promethazine (promethazine ( 异丙嗪异丙嗪 ) false-negative ) false-negative urine results. urine results. （（ 22 ）） anti-convulsants, anti-anti-convulsants, anti-parkinson drugs, hypnotics, and parkinson drugs, hypnotics, and tranquilizers false-positive results. tranquilizers false-positive results.

３３ .Special test: hCG kits can detect a .Special test: hCG kits can detect a wide and varying range of different wide and varying range of different hCG-related molecules in serum or hCG-related molecules in serum or urine samples. urine samples.

The molecules detected include The molecules detected include

5 groups:5 groups:

1).non-nicked hCG (1).non-nicked hCG ( 完整的完整的 HCG) the HCG) the active hormoneactive hormone

2).nicked hCG 2).nicked hCG （缺口（缺口 hCGhCG ））

3).hyperglycosylated HCG(3).hyperglycosylated HCG( 高糖基化高糖基化HCG)HCG) 最新研究表明如果此型最新研究表明如果此型 HCGHCG 在妊娠在妊娠七周时维持在较高水平不下降则预示妊娠七周时维持在较高水平不下降则预示妊娠异常异常

4).asialo hCG (4).asialo hCG ( 缺乏唾液酸基的缺乏唾液酸基的 HCG), HCG), 5) hCG-CTP or free ß-subunit can 5) hCG-CTP or free ß-subunit can

ⅢⅢWhat is the clinical What is the clinical significance?significance?

1. Normal pregnancy1. Normal pregnancy

FIGUREFIGURE

The "normal" ranges for the HCG in The "normal" ranges for the HCG in blood pregnancy test blood pregnancy test

1) The concentration of may reach up to 1) The concentration of may reach up to 150,000 mIU/ml in both serum and urine. 150,000 mIU/ml in both serum and urine.

2)hCG levels rise exponentially for the first 2)hCG levels rise exponentially for the first 8 weeks of pregnancy,8 weeks of pregnancy,

3) reaching a peak at 10 weeks after the 3) reaching a peak at 10 weeks after the last menstrual period. last menstrual period.

4)In the following 10 weeks levels slowly 4)In the following 10 weeks levels slowly decline to approximately one fifth of peak decline to approximately one fifth of peak levels and remain around one fifth of peak levels and remain around one fifth of peak levels until term levels until term

2. 2. Early pregnancy loss (EPL) Early pregnancy loss (EPL)         This is an embryo which fails to     This is an embryo which fails to implant properly in the uterus, or is implant properly in the uterus, or is rejected by the uterus. It is followed rejected by the uterus. It is followed by a normal or slightly heavier than by a normal or slightly heavier than normal menstrual period. normal menstrual period.

hCG concentration reaches a peak hCG concentration reaches a peak after 2 weeks conception (28 days after 2 weeks conception (28 days after start of last menstrual period) after start of last menstrual period) at 10 to 100 mIU/ml, then rapidly at 10 to 100 mIU/ml, then rapidly declines. Normal or slightly heavier declines. Normal or slightly heavier than normal menses follow. than normal menses follow.

3. 3. Ectopic or extrauterine Ectopic or extrauterine pregnancypregnancy       In women with extrauterine or In women with extrauterine or ectopic pregnancies, unduly low hCG ectopic pregnancies, unduly low hCG levels may be detected. levels may be detected.

最新研究表明如果腹腔血最新研究表明如果腹腔血 beta-HCGbeta-HCG 定性定性检查为阳性者检查为阳性者 100%100% 为异位妊娠为异位妊娠

4 Gestational Down syndrome4 Gestational Down syndrome 5 Hydatidiform mole5 Hydatidiform mole hCG hCG

concentration may be as high as concentration may be as high as 2,000,000 mIU/ml. 2,000,000 mIU/ml.

6 Persistent trophoblast 6 Persistent trophoblast disease or persistent moledisease or persistent mole

7 Choriocarcinoma7 Choriocarcinoma 8. Germ cell, bladder and other 8. Germ cell, bladder and other

non-trophoblastic malignanciesnon-trophoblastic malignancies    9. pituitary hCG production9. pituitary hCG production        10. false positive hCG production10. false positive hCG production

Ⅳ Ⅳ HPT( Home pregnancy tests) HPT( Home pregnancy tests) use midstream urine use midstream urine you need to hold the absorbant you need to hold the absorbant

tip of the stick in the cup of urine tip of the stick in the cup of urine for 5-10 seconds for 5-10 seconds

In the result window, the tests In the result window, the tests usually give a line or a plus.usually give a line or a plus.

Examples of line Examples of line tests.doctests.doc