A diagnosis of Turner syndrome is based upon identification of characteristic symptoms, a detailed patient history, a thorough clinical evaluation, and a variety of specialized tests. Turner syndrome should be suspected in girls with growth deficiency or short stature of unknown cause.

Clinical Testing and Workup
A diagnosis of Turner syndrome is often confirmed by chromosomal analysis, which is usually achieved by determining the karyotype. Karyotyping is a laboratory test that evaluates the number and structure of chromosomes. Karyotyping can be done on almost any type of tissue. In most cases, a blood sample will be taken and used to ascertain a person's karyotype.

Turner syndrome is being increasingly diagnosed before birth (prenatally) based on chromosomal analysis performed subsequent to amniocentesis or chorionic villus sampling (CVS). During amniocentesis, a sample of fluid that surrounds the developing fetus is removed and analyzed, while CVS involves the removal of tissue samples from a portion of the placenta.

In certain cases, certain physical findings associated with Turner syndrome may be seen on a fetal ultrasound. For example, the accumulation of lymph fluid near the neck of a developing fetus can sometimes be seen on a routine fetal ultrasound.

Specific imaging techniques such as magnetic resonance imaging (MRI) may be performed to assess affected individuals for the presence of symptoms potentially associated with Turner syndrome such as liver, kidney or heart abnormalities. An MRI uses a magnetic field and radio waves to produce cross-sectional images of particular organs and bodily tissues. Many individuals with a diagnosis of Turner syndrome undergo a complete cardiac workup to assess the structure and function of the heart. This will include an echocardiogram.

Additional evaluation should be done on thyroid and liver function, bone age, and growth. Hypertension screening should also be performed. Infants diagnosed at birth should receive a full ear, nose and throat examination including an auditory exam. Children, especially those who experience repeated otitis media, as well as adults, require periodic hearing evaluation. Affected individuals should also undergo thyroid function tests because of the potential for thyroid disease.