Endocrine Abstracts

Introduction: Reference ranges for classifying a patient as hyper-, normo- and hypothyroidism vary from one laboratory to another, because the techniques used, regional factors (race, iodine..), but there is also the variables of age and sex of the patient are not taken. Article Thyroid Volume 21, Number 1, 2011, 5–11 Boucai et al, published equations to adjust the normal range in terms of these variables. Evaluate these equations and see if there are significant changes to normal.

Materials and Methods: We studied 520 outpatients that have requested TSH from the health center.

Our reference range for TSH is between 0.35 and 4.94 mUI/mL, so adapting the equations described in the article the following equations are obtained to study:

TSH(2.5)=0.35+0.00073*Age−0.031*Sex

TSH(97.5)=4.94+0.05*Age−0.223*Sex

Considering age in years and sex 0 for men and 1 for females

Results: With our classification reference range of thyroid function: are 12 hyperthyroid patients (2.3%), normothyroid are 472 (90.8%) and hypothyroid are 36 (6.9%). Applying the equations to study the following results: 13 (2.5%), 498 (95.7%) and 9 (1.8%) respectively.

hyperthyroid patients have antibodies and the patient requested the equation presented discrepant antibody negative. Of the 36 hypothyroid patients, only 14 had requested antibodies, with 28% negative.

patients with negative antibodies with the equation would be reclassified as normothyroid. But of the 10 patients with positive antibodies, 5 would remain hypothyroid and the other 5 would then normothyroid.

Conclusions: These equations to determine new TSH reference ranges are attractive because they allow us to dispense with the verification of results, enlargement of new assays, such as T4, T3 or antibodies. As we have only tested on a working day studies are higher, increasing the size of the sample, obtained by decades of age groups homogenous and making sure that all the patients studied made antibodies present.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector