Increasing Incidence, but Lack of Seasonality, of Elevated TSH Levels, on Newborn Screening, in the North of England

Table 1

TSH newborn screening base, assay methodology, and cut-off values during the study period.

	1994–March 1998	April 1998–February 2003	March 2003–March 2005	April 2005–present
Centre	Newcastle	Durham	Durham	Newcastle
Method	Radioimmunoassay	ACS-180	DELFIA	DELFIA
	(Manual)	(Bayer)	(Perkin Elmer)	(Perkin Elmer)
TSH cut-off (mU/L)	20	10	6	6