Pregnancy Associated Plasma Protein-A (PAPP-A), Serum


PAPP-A is a 750 kDa glycoprotein produced specifically by trophoblasts. Therefore, it can only be found in pregnant plasma. It is detectable as early as 8 wks of gestation and then rises throughout pregnancy. In Down’s syndrome, maternal serum PAPP-A levels, when measured between week 8 and 13 of gestation, are significantly reduced with an average decrease of 2.5 times. Furthermore, the correlation between serum and tissue (placental) expression levels of PAPP-A is lost in Down’s pregnancies. PAPP-A, and Free hCG, can be used in combination with the ultrasound Nuchal Translucency test to enhance the detection rate of Down’s syndrome and other foetal abnormalities.


PAPP-A is a powerful screening tool for Down’s syndrome pregnancies. It has the advantage of achieving satisfactory results as early as the first trimester and provides the highest detection rate for Down’s syndrome through early screening.

Sample Type, Quantity & Conditions

1 ml Serum Stability: 24 Hours at 2-8 °C 2 Months at -20 °C

Special Precautions

Avoid grossly haemolysed or grossly lipemic samples.

Normal Range

By Report

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