Dual Marker Report – Explainer

Maternal screening for genetic disorders is an important step in all pregnancies. There is a growing awareness and usage of various biochemical screening tests such as dual marker and quadruple markers. Many a times clinicians and patients have found it difficult to understand a screening report. Here is an explainer to help you understand the various sections in the LABASSURE maternal screening report. This report needs to interpreted by the doctor/clinician and discussed with patients to arrive at the next steps.

A Dual Marker OR Double Marker Report is a very important report amongst a battery of tests administered during a course of a pregnancy. It is a part of the Maternal Serum Screening, also known as Biochemical Screening which is performed during pregnancy to screen for the risks of downs syndrome or other common genetic abnormalities.

What is Biochemical Screening

A biochemical screening test as the name suggests is based on the evaluation of the level of certain biochemical in the body. In case of Dual Marker, it is Free B-HCG and PAPPA. The measurement of these biochemicals is compared against the reference data which is based on various characteristics such as ethnicity, age, weight, gestation age etc. The comparison leads to a risk estimation or the probability of a genetic disorder.

Similar to Dual Marker, there are Triple Marker and Quadruple Marker tests which use three and four biochemical parameters respectively. They are meant to be used for different gestation ages. A dual marker is applicable between 11 to 14 weeks. Beyond 14 weeks, one would need to do a Triple or Quadruple test.

Since this is a probability or estimation of risk, the estimate is as good as the measurements and the reference data. If the measurements are not very accurate or the reference data and algorithm is not good, then the risk estimation will be poor.

We at Labassure, are using the Cobas e411 from Roche to measure the biochemical levels. The Roche platform is known for its accuracy and higher concordance. It is one of the platforms approved by the Fetal Medicine Foundation (UK) for biochemical screening.

Biochemical Screening with NT

The biochemical screening estimates are further improved by adding the CRL and NT measurements obtained from a level – II Ultrasound scan. Needless to say the Ultrasound should be performed by an experienced Sonologist or Fetal Medicine Expert who has the training and experience in taking various fetal measurements like CRL, NT and others.

It is always recommended that the screening combines both the Biochemical as well as Ultrasound findings. This improves the accuracy of the risk estimation.

Understanding a Screening Report

Some of patients and referring doctor have queries with respect to the report and the risk estimates in the report. Here is a quick guide to help you understand the report.

Screening for genetic disorders is a very important step during pregnancy. It can help assure the expecting parents about the health of their baby and prepare them for any risks/adverse outcomes. It also helps clinicians in making important decisions about the pregnancy, maternal and fetal treatments, interventions and delivery. Hence choosing an experienced and reliable clinician, ultrasound expert and laboratory partner becomes important. 

Hope this article helps you understand the maternal screening report better. For any further queries, please write to info@labassure.com


1. Fetal Medicine Foundation, London. https://fetalmedicine.org/
2. Package insert Elecsys PAPP-A and Elecsys free ß-hCG . Roche Diagnostics.
3. Roche multicenter Evaluation Study. Data on file, 2009.
4. SsdwLab Software https://www.sbpsoftware.com/SsdwLab-5.html