CSF tap test explained

CSF tap test
Purpose:	test to decide shunting of cerebrospinal fluid
Synonyms:	Lumbar tap test

The CSF tap test, sometimes lumbar tap test or Miller Fisher Test, is a medical test that is used to decide whether shunting of cerebrospinal fluid (CSF) would be helpful in a patient with suspected normal pressure hydrocephalus (NPH). The test involves removing 30-50 ml of cerebrospinal fluid (CSF) through a lumbar puncture, after which motor and cognitive function is clinically reassessed.^[1] The name "Fisher test" is after C. Miller Fisher, a Canadian neurologist working in Boston, Massachusetts, who described the test.^[2]

Clinical improvement showed a high predictive value for subsequent success with shunting. A "negative" test has a very low predictive accuracy, as many patients may improve after a shunt in spite of lack of improvement after CSF removal.^[3]

Notes and References

1. Virhammar . J. . Cesarini . K. G. . Laurell . K. . 2011-07-30 . The CSF tap test in normal pressure hydrocephalus: evaluation time, reliability and the influence of pain . European Journal of Neurology . 19 . 2 . 271–276 . 10.1111/j.1468-1331.2011.03486.x . 21801282 . 22058194 . 1351-5101.
2. Book: Collins LG, Rovner BN, Marenberg MM. Arenson C, Busby-Whitehead J, Brummel-Smith K, O'Brien JG, Palmer MH, Reichel W. Reichel's care of the elderly : clinical aspects of aging.. 2009. Cambridge University Press. Cambridge. 9780521869294. 180. 6th . https://books.google.com/books?id=74FPjVwzGDUC&dq=%22fisher%20test%22%20NPH&pg=PA180. Evaluation and Management of Dementia.
3. Wikkelsø, C., Hellström, P., Klinge, P. M., Tans, J. T. J., & European iNPH Multicentre Study Group . Petra Klinge. The European iNPH Multicentre Study on the predictive values of resistance to CSF outflow and the CSF Tap Test in patients with idiopathic normal pressure hydrocephalus . Journal of Neurology, Neurosurgery, and Psychiatry . 2013 . 84 . 5 . 562–568 . 10.1136/jnnp-2012-303314 . 23250963. 6335882 .