Markers of Blood tetst at 16-17 weeks of pregancy for congenital abnormalities & aneuploidy

Quadruple Markers.

Triple Markers-serum markers for anomaly & Chromosomal (T-221 & T 18) & open NTD abnormalities. Three /Four parameters in serum are assessed e.g. AFP (ng/ml.); HCG (mIU/ml) & Estriol in ng/ml & Inhibin-B.

Three   diseases are screened e.g. a) NTD: - Cut off value is if > 2.5 MoM: Calculated risk by PRISCA.

 b) Trisomy-13:- Cut off 1:250 and Trisomy risk is if cut off is 1:100.

Abnormality.	Cut Off  Values	Detection rate	False positive.
NTD	If > 2.5 MoM	70-75%	2-4%
Trisomy 21	1: 250.	65%	5%
Trisomy-18	1:100	60%	0.3%

Interpretation of each value as per gestational age.

G A.	AFP in ng/ml	HCG mIU/ml.	Free E3 ng/ml	In patients case the results were-
16 wks	37	25,690	0.76
18 weeks	52	16340	1.25
19 weeks	61	13040	1.5
20	72	10,400 mIU/ml	1.7 ng/ml

Lab reports will vary on 1) Smoking, 2) Age, race ethnicity 3) Twins    4) Insulin Dependent DM  5)  IVF pregnancy 6) previous birth of Down s syndrome affected baby  7)  Maternal body weight 9) Gest age .

Quad Scan Serum Markers in Second Trimester.

1)       MSAFP:- Maternal serum Alpha Fetoprotein:-This protein is best carried out at 16-18 weeks of pregnancy, In Downs cases the median MSAFP is median of 0.7% i.e. in Downs foetus the maternal serum AFP is almost always less that the average –usually < 0.7. However, in twin gestations the values is 2.5 MoM for single pregnancy. But not all Down will have low MSAFP but only 20-35% of all Down babies have low values. MSAFP values need correction for weight, race, diabetes, twins. In insulin dependent DM –in such diseases the values will be automatically about 60% less. Therefore in statistical evaluation by software such factors have to be included e.g. Factors to be considered are age, smoking, Weight, height, Race, Gest age, Diabetes, Twin, NT scan.

Markers – that are assayed:-

Marker.	Net value in IU/ml	Expressed as MoM.	Normal range as per wk of gest is	Quoted below.
AFP	32.6 IU/ml.	0.621 As example.
hCG	26.6 IU/ml.	0.794 For instance.
U-E3	1.3 ng/ml	0.411 MoM

In a given patient’s the final results are as follows:

AFP levels in healthy singleton foetus.

Level of AFP as per gest age.ng/ml.	Level & Range quoted as abnormal.
15 wks: 16-70 ng/ml.
16   wks.  :  21-92. ng/ml
17 wks:   24-105.