Diagnostic comparison between cord blood and filter paper for the screening of congenital hypothyroidism

BACKGROUND:- Congenital hypothyroidism (CH) is the most common preventable cause of mental retardation. Screening for congenital hypothyroidism can be helpful in preventing mental retardation among general population. Umbilical cord blood TSH (CBTSH) estimation has been universally accepted and is one of the most cost effective screening programs in the field of preventive medicine and public health. AIMS AND OBJECTIVES:- This study was aimed to find the effectiveness of cord blood TSH as a screening tool for congenital hypothyroidism. MATERIALS AND METHODS:- This hospital based cross sectional study was conducted at GCS Medical College Hospital & Research Centre, Ahmedabad, over a period of one year in 1687 neonates. All newborns delivered at the institute were subjected to cord blood TSH level estimation and a repeat Serum TSH estimation was done at or after 72 hours of life. Diagnosis of congenital hypothyroidism is confirmed postnatally by standard Serum TSH value cut offs as per age. Data collected and statistically analysed. RESULTS:- Out of 1687 neonates born during the study period, 1548 formed the study group. 805 (52%) were males and 743(48%) were females. The birth weight of babies ranged from 850 gms to 4300 gms. The value of CBTSH varied from 1.3mIU/L to 101.4mIU/L with mean CBTSH of 7.21mIU/L. 28(1.8%) babies had CBTSH levels >20mIU/L. Out of which four were later diagnosed to have congenital hypothyroidism. All four had CBTSH levels >20mIU/L. All other neonates with CBTSH levels less than 20mIU/L were found to have normal screening later postnatally. CONCLUSION:- The current study concludes that cord blood TSH is a sensitive marker to screen for congenital hypothyroidism in neonates. A cut off value of cord blood TSH >20mIU/ml can be used for screening purpose.

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Screening for Congenital Hypothyroidism With Specimen Collection at Two Time Periods: Results of the Northwest Regional Screening Program

PEDIATRICS ◽

10.1542/peds.76.5.734 ◽

1985 ◽

Vol 76 (5) ◽

pp. 734-740

Author(s):

Stephen H. LaFranchi ◽

Cheryl E. Hanna ◽

Patricia L. Krainz ◽

Michael R. Skeels ◽

Richard S. Miyahira ◽

...

Keyword(s):

Congenital Hypothyroidism ◽

Filter Paper ◽

Age Of Onset ◽

Screening Program ◽

Thyroid Tissue ◽

Cost Effective ◽

Thyroid Stimulating Hormone ◽

Primary Hypothyroidism ◽

Skeletal Maturation ◽

Second Screen

To determine the benefit of collecting two routine specimens to test for congenital hypothyroidism, we examined the results of our newborn screening program during the last 9.5 years. The Northwest Regional Screening Program (NWRSP) performs a primary thyroxine test with thyroid-stimulating hormone determinations on the lowest 10% of dried blood filter paper specimens. An initial specimen is obtained in the newborn period, and a routine second specimen is collected at approximately 4 to 6 weeks of age in all infants born in Oregon and 25% of infants born in Idaho, Montana, Alaska, and Nevada. Between May 1975 and October 1984, 182 infants with primary hypothyroidism were detected from 811,917 infants screened, a prevalence rate of 1:4,461. The routine second specimen led to the diagnosis of 19 infants of 484,604 infants screened, a detection rate of 1:25,505. When infants detected by the second screen were compared with those detected by the first screen, they had higher thyroxine and lower thyroidstimulating hormone concentrations on filter paper and serum specimens. When thyroid scanning was used, all but one infant detected by the second screen had some residual thyroid tissue, whereas 35% of infants detected by the first screen had thyroid aplasia. Skeletal maturation was more likely to be normal in infants detected by the second screen. These infants appear to have milder hypothyroidism due to a later age of onset or slower evolution of thyroid failure. At a cost of $31,881 per infant detected by the second screen, the NWRSP found it cost-effective to obtain a routine second specimen.

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Immunofluorometry of thyrotropin, from whole-blood spots on filter paper, to screen for congenital hypothyroidism.

Clinical Chemistry ◽

10.1093/clinchem/32.10.1854 ◽

1986 ◽

Vol 32 (10) ◽

pp. 1854-1856 ◽

Cited By ~ 12

Author(s):

J Arends ◽

B Nørgaard-Pedersen

Keyword(s):

Monoclonal Antibodies ◽

Congenital Hypothyroidism ◽

Filter Paper ◽

Clinical Evidence ◽

Type System ◽

Time Resolved ◽

Sandwich Type ◽

Blood Specimens ◽

Positive Results ◽

Paper Disc

Abstract We have evaluated a time-resolved immunofluorometric assay (IFMA) for determining thyrotropin. This "sandwich"-type system involves two monoclonal antibodies directed against different epitopes. A linear relationship between signal and thyrotropin concentration was observed up to 6000 milli-int. units/L. This procedure takes one day, vs six days with our present RIA technique, and requires only a tenth as much sample. Furthermore, intra- and interassay CVs are lower than with RIA. Assay of 19 paper-disc blood specimens from newborns identified as having congenital hypothyroidism, both by RIA and by clinical evidence, also gave positive results with IFMA. In prospective assay of 3944 specimens by both methods we identified one case of congenital hypothyroidism, which was detected by both techniques. Technical false-positive reactions, identified as such by repeated analyses, were fewer with the IFMA method than with RIA.

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