What does MOM value in the results of the Tandem Mass Spectrometry Screening test mean?

Patient's question:

No

Doctor's answer:

MOM value refers to the median multiple. For any analyte, the MOM value is the ratio of a test concentration (e.g., testing HCG, requiring pregnant women of the same gestational age tested in the same laboratory) to the expected (normal) median concentration of that analyte. Using MOM values can avoid interlaboratory systematic biases and allow for standardization of gestational age. Since the median is not affected by external random factors, the average is typically not used.