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TSH and thyroxine in stored neonatal filter-paper blood samples from patients with congenital hypothyroidism
Insights
Newborn screening for congenital hypothyroidism (CH) is most effective using thyroid-stimulating hormone (TSH) analysis. A TSH cut-off of 50 mU/l on filter paper blood samples ensures high detection rates for CH.
Area of Science:
- Pediatrics
- Endocrinology
- Neonatal Screening
Background:
- Congenital hypothyroidism (CH) is a treatable condition requiring early diagnosis.
- Current diagnostic methods may not identify all CH cases neonatally.
- Neonatal screening is crucial for timely intervention and preventing developmental issues.
Purpose of the Study:
- To evaluate the effectiveness of TSH and thyroxine measurements in neonatal blood samples for congenital hypothyroidism screening.
- To determine the optimal cut-off level for TSH analysis in filter paper blood samples for CH detection.
- To compare the sensitivity and recall frequency of TSH-based versus thyroxine-based screening programs.
Main Methods:
- Retrospective analysis of neonatal filter paper blood samples from infants with confirmed congenital hypothyroidism (n=41 for TSH, n=16 for thyroxine).
- Comparison with blood samples from control infants.
- Simulation of screening program performance using different analytical methods and cut-off values.
Main Results:
- Neonatal TSH analysis with a cut-off limit of 50 mU/l of plasma would have detected all congenital hypothyroidism cases.
- Thyroxine analysis for screening would necessitate a significantly higher recall rate to achieve comparable sensitivity.
- TSH analysis on PKU filter paper blood samples is a sensitive method for neonatal CH detection.
Conclusions:
- TSH analysis of neonatal filter paper blood samples is a highly effective method for congenital hypothyroidism screening.
- A cut-off limit of 50 mU/l of plasma for TSH is recommended for nationwide CH screening programs.
- Implementing a TSH-based screening program can ensure early detection and treatment of CH, improving infant outcomes.
Abstract:
Filter paper blood samples collected neonatally from infants with congenital hypothyroidism were analysed retrospectively for TSH (n = 41) and thyroxine (n = 16). The patients were detected by clinical signs and symptoms and treatment was started during the first two years of life. Similar blood samples from control infants were analysed for comparison. All CH patients would have been detected neonatally if screening had been based on TSH analyses with a cut-off limit corresponding to 50 mU of TSH/l of plasma. A screening programme involving analyses of thyroxine would require considerably higher recall frequency to yield 100% sensitivity. These results support a nationwide CH screening program based on TSH analyses of PKU filter paper blood samples using 50 mU/l of plasma as the cut-off limit.