Alpha Foetoprotein

(AFP)

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Features

- Assits in Dx of foetal abnormalities

- Also used as tumour marker

 

Alpha Fetoprotein (AFP)

- Produced by liver of foetus 

- Levels reach adult levels within 8-12 months

-  Produced in very small amounts by adults

- Small amount secreted by kidneys of foetus into amniotic fluid

- Passes from amniotic fluid into maternal circulation

- Levels rise through pregnancy

 

Levels in Pregnancy

- Most accurate between 15-18 weeks gestation to detect foetal anomalies

- Abnormalities indicate need for foetal ultrasound + amniotic fluid AFP

- Decreased

- Trisomy 21 (Down Syndrome)

- Trisomy 18 (Edwards Syndrome)

- Diabetes Mellitus

- Increased

-  Incorrect gestational age

-  Foetal demise

-  Multiple gestations (twins..)

-  Placental abruption

-  Neural tube defects

-  Spina bifida

-  Anencephaly

-  Abdominal wall defects

-  Oomphalocoele

-  Gastroschesis

-   Levels higher than Oomphalocoele

-  Levels may also be elevated in acute hepatitis, colitis & ataxic telangiectasia

 

Tumour Marker

- Secreted by neuroblastoma, hepatoblastoma, hepatocellular carcimona (HCC), endodermal sinus tumour

- Used to determine efficacy of treatment for testicular cancer, ovarian cancer & malignant teratoma

- In HCC not good for Dx but useful in assessing response to Mx