Utilization and diagnostic yield of neurogenetic testing at a tertiary care facility
Kerstin L Edlefsen1, Jonathan F Tait, Mark H Wener
1Department of Laboratory Medicine, University of Washington School of Medicine, Seattle, WA 98195-7110, USA.
Background:
Institutions face increasing charges related to molecular genetic testing for neurological diseases. The literature contains little information on the utilization and performance of these tests.
Methods:
A retrospective utilization review was performed to determine the diagnostic yield of neurogenetic tests ordered during calendar year 2005 at a large academic medical center in the western United States.
Results:
Overall, a relevant mutation was identified in 30.2% of the 162 patients tested and in 21.5% of the 121 probands, defined as patients for whom no mutation has been previously identified in a family member. Patients with muscle weakness (n = 65) had a mutation detected in 26.2% of all patients and 23.5% of probands (n = 51), with an estimated testing cost per positive result of $3190. Patients tested for neuropathy (n = 36) had a mutation detected in 27.8% of patients and 22.6% of probands (n = 31), with an estimated cost per positive result of $5955. Patients with chorea (n = 25) had a positive result obtained in 68% of patients and 71.4% of probands (n = 7); the estimated cost per positive test was $440. Other diagnostic categories evaluated include ataxias (n = 18; yield, 11.1%; $7620 per positive), familial stroke or dementia syndromes (n = 8; yield, 12.5%; $6760 per positive), and multisystem mitochondrial disorders (n = 10; yield, 20%; $6485 per positive).
Conclusions:
Expert clinicians at a tertiary care center who ordered neurogenetic tests obtained a positive result in 21.5% of patients without previously identified familial mutations. These results can be used for comparison and to help establish utilization guidelines for neurogenetic testing.
