THE NEED FOR STANDARDIZED BLOODSPOT TSH-CALIBRATORS IN CONGENITAL HYPOTHYROIDISM SCREENING

Introduction: The preparation of bloodspot calibrators and quality con trol samples for neonatal thyrotropin (TSH), as part of the national q uality assessment scheme in The Netherlands, is sometimes problematic. Often, the recovery of the added TSH is well above 100% when measured in plasma. Results from other External Quality Assessment Schemes for neonatal TSH show similar problems. Methods and Results: A questionna ire was sent to 17 kit manufacturers and organizers of EQAS concerning the preparation of bloodspot calibrators for TSH; 13 completed questi onnaires were returned. There are large differences with respect to ty pe of filterpaper, matrix, assessment of TSH-concentrations to the cal ibrators, size of the bloodspots, shelf life, etc. Discussion: Attenti on is focused on several items to be considered when attempting standa rdization of the preparation of TSH bloodspot calibrators.