COMPARATIVE STUDY BETWEEN TWO
DIFFERENT METHODS FOR QUANTIFICATION
OF TSH IN NEWBORN SCREENING
Goldbeck, A.S.*; Moreira, M.D.G.*; Sampaio Filho,C.A.**
*Faculdade de Farmácia/ UFRGS/ Porto Alegre/ RS/Brasil
* Serviço de Referência em Triagem Neonatal (SRTN)/ Hospital Materno Infantil Presidente Vargas/ Porto
**Departamento de Pesquisa e Desenvolvimento da Intercientífica/SP/Brasil
Rio Grande do Sul State Public Health Department perform newborn screening for Congenital
Hypothyroidism (CH) for 10.000 samples per month. The State Reference Center is the
Laboratory of Faculdade de Farmácia da UFRGS , where the samples are evaluated using the
methodology of “time resolved fluoroimunoassay” for quantification of Thyroid Stimulating
Hormone (TSH) as primary screening for all the samples.
A new technology using a fluorimetric method with
multi analysis format (multiplex) based on set of
microspheres, have been used in our laboratory
for a comparative study and validation in the
routine. This platform can measure Thyroid
Stimulating Hormone (TSH) and Thyroxin (T4) at
same time in the same sample. This feature gives
to the Laboratory the ability to detect Central CH
and the feasibility to speed up the evaluation and
confirmation of the classical forms of CH.
In this study were used just TSH as parameter for the comparative study and validation of test,
running a total of 2.000 samples in both methods. The results presented by 1.998 samples were
below the cut-off point established by the Laboratory for TSH (20,0 uUI/mL serum) and 2 samples
with values above the cut-off limit in both methods. Using the multiplex technology, 2 samples
detected presented low values for T4 (6,0 ng/dL) and in all other samples, T4 values were inside the
CONCLUSION: both methods are similar concerning the results of TSH,
with the advantage for multiplexing method, which offers simultaneous
analysis of TSH and T4;
The possibility to detect Central CH must be considered
as significant and it helps the State Newborn Screening Program to have a
better evaluation of the first primary screening for classical CH;
Other advantages of the use of multiplex fluorimetric
method are the potential to include other parameters with cost benefit
and minimize the usage of sample performing all the assays at same time
using one single punch of the sample.
•No Central CH were diagnosed.
•The correlation coefficient (R²) between the methods was 0.99.
•Considering all the possible variation between the samples collection and punch spot area, it
was evident the excellent correlation between methods.
Coverage of Newborn Screening Programme
Rio Grande do Sul - BRAZIL
1997 1998 1999 2000 2001 2002 2003 2004 2005