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Objectives: Clinical laboratories store filter paper samples used in neonatal screening for various periods of time after performing hormonal measurements. However, due to lack of data concerning specimen stability, it is unclear for how long these samples should be stored. The objective of this study is to determine the stability and reproducibility of thyroid-stimulating hormone (TSH), thyroxine (T(4)) and 17-hydroxyprogesterone (17-OHP) measurements in filter paper blood samples stored for up to 60 months., Methods: Two hundred and twenty-eight blood samples, drawn between the second and the fourth day of life, were divided into seven distinct groups and kept at 4-8 degrees C for one day or 2, 12, 24, 36, 48 or 60 months after basal hormonal measurements. In each group, TSH, T(4) and 17-OHP levels were initially assayed 24-48 hours after collection (basal) and repeated once at the end of storage timing. All the measurements were performed by time-resolved fluorometry (1235 AutoDELFIA, Wallac Oy, Turku, Finland). Repeated and basal levels of each hormone were compared within the same group by Student's paired t-test. Differences were considered significant at P < 0.05., Results: Compared with basal measurements, TSH and T(4) levels declined significantly only when these hormones were re-assayed at 48 or 60 months of sample storage. In contrast, 17-OHP concentrations decreased earlier, starting at 24 months and continuing throughout the remaining period., Conclusion: Our data suggest that neonatal screening of filter paper samples kept at 4-8 degrees C are reliable for repeating the hormonal measurements when specimens are stored for up to one year, in the case of 17-OHP, or three years, in the case of T(4) and TSH.

Objective: Symptoms of hypothyroidism in adults can be mistaken for medical and psychiatric diseases, as well as for general signs of ageing such as weakness, lethargy and fatigue. The incidence of hypothyroidism is many-fold higher in adults than in newborn children. The latter have been routinely screened for the condition using filter paper dried blood spots (DBS) for nearly three decades but this cost-effective screening technique has only recently been applied to adults. This study was undertaken to show that DBS testing in adults and older children is an accurate way to screen for hypothyroidism., Methods: Serum and DBS specimens were collected from adults and children. Assays were run on both specimens and the results correlated. In addition 972 specimens were collected from adults at community centres and nursing homes. Follow-up studies were performed on patients with positive results., Results: The correlation coefficient for 118 matched serum and DBS specimens was 0.99. Thyroid-stimulating hormone (TSH) values were elevated in 50 of the 972 adults from nursing homes and community centres. Thirteen of these individuals were on thyroid medication and 28 had either high serum TSH or high thyroglobulin (TgAb) or thyroid peroxidase (TPOAb) antibody levels., Conclusions: Individuals can be screened for hypothyroidism by collecting finger stick DBS specimens at community centres, nursing homes and other locations which can be mailed by regular postal service to a central laboratory for accurate and inexpensive testing.

Objectives: Phenylketonuria (PKU) is a genetic disease with autosomal recessive inheritance. In Poland the microbiological Guthrie test for this disease was replaced by an enzymatic colorimetric test. The question is whether the colorimetric test might be used in monitoring treatment of PKU., Setting: In 80 patients with PKU on routine treatment monitoring of serum phenylalanine concentrations (SPh) was compared with phenylalanine concentrations in blood on filter paper (PhBFP)., Methods: Measurements of SPh were by a fluorimetric method (McCaman and Robins), and those of PhBFP were by an enzymatic colorimetric method., Results: The regression analysis of SPh compared with PhBFP gave the equation y=0.9219x+0.2389; for the reversed ratio: it gave y=1.0220x+0.55083. The correlation was 0.97 at p<0.05., Discussion: Concentrations of SPh accepted for children with PKU are not uniform. In the Cracow centre, the range of accepted SPh concentrations are 2-6 mg/dl for children and <12 mg/dl for older patients. The concentrations of PhBFP accepted are somewhat higher than SPh, range from 4 to 10 mg/dl, and are a good indicator of an appropriate diet., Conclusions: (1) The comparison indicated that colorimetric measurements of PhBFP are effective in monitoring therapeutic PKU management. Tests can be performed more often and are more comfortable both for the patients and their parents. (2) The comparative results indicated a concentration of PhBFP ranging from 4 to 10 mg/dl to be the accepted value for children treated for PKU.