Prenatal Diagnosis and Ultrasound
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Principles of screening, Screening for Down's syndrome, Diagnosis of abnormalities, Diagnosis of genetic disorders, Fetal hydrops and anaemia, Ultrasound, Diagnostic invasive procedures, Weblinks.
Principles
of screening
Patients and doctors alike are used to associating an investigation
with the confirmation or exclusion of a diagnosis. It is not surprising,
therefore, to find that an enormous amount of anxiety can be created
by the use of screening tests, particularly in pregnancy, where so much
is at stake. Screening tests simply select populations into low and
high risk groups, for the purpose of planning the next level of care
for a particular issue or diagnosis. They can be useful in a variety
of situations in pregnancy. It is essential that the patient understands
the nature of a screening test before agreeing to the investigation,
so that true informed consent is obtained, to minimise the anxiety of
a false positive result, and appreciate the possibility of a false negative
result. The situation is made more confusing by the fact that many diagnostic
tests applied to the whole population are described as 'screening',
using the lay, rather than scientific meaning of the word.
