TSH assay


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assay

 [as´a]
determination of the purity of a substance or the amount of any particular constituent of a mixture.
biological assay bioassay; determination of the potency of a drug or other substance by comparing the effects it has on animals with those of a reference standard.
CH50 assay a test of total complement activity as the capacity of serum to lyse a standard preparation of sheep red blood cells coated with antisheep erythrocyte antibody. The reciprocal of the dilution of serum that lyses 50 per cent of the erythrocytes is the whole complement titer in CH50 units per milliliter of serum.
enzyme-linked immunosorbent assay (ELISA) any enzyme immunoassay using an enzyme-labeled immunoreactant (antigen or antibody) and an immunoadsorbent (antigen or antibody bound to a solid support). A variety of methods are used for measuring the unknown concentration, such as either competitive binding between the labeled reactant and unlabeled unknown or a sandwich technique in which the unknown antigen binds both the immunoadsorbent and labeled antibody. One of the uses of ELISA is to screen blood for antibody to the human immunodeficiency virus; a positive result indicates probable exposure to the virus and possibly that the virus is in the blood. Since false-positives can occur, a back-up test is used to confirm positive findings.
 ELISA: With antigen capture ELISA, the wells are coated with antibody to the virus. The sample containing virus (1) is added and, after washing several times, enzyme conjugated to an antibody to the virus is added (2). Finally, after a further cycle of washing, the enzyme's substrate (3) is added. A colored product is formed if the viral antigen is present in the sample (4). From Hart and Shears, 1997.
microhemagglutination assay–Treponema pallidum (MHA-TP) a Treponema pallidum hemagglutination assay using microtechniques; used in the detection of syphilis.
radioreceptor assay a radioligand assay in which a radiolabeled hormone is used to measure the concentration of specific cellular receptors for the hormone in tissue specimens, an example being radioassay of estrogen receptors in breast tissue.
thyroid-stimulating hormone assay thyroid-stimulating hormone test.
Treponema pallidum hemagglutination assay (TPHA) a treponemal antigen serologic test for syphilis using tanned sheep red blood cells coated with antigen from the Nichol's strain of Treponema pallidum and treated patient serum; it is similar in sensitivity and specificity to the FTA-ABS test. This test is not useful for individuals who have had syphilis in the past.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
References in periodicals archive ?
However, while the device is considered to be in its investigational stage of development, assuming the successful completion of verification and validation, Zomedica expects to commence marketing the TRUFORMA(TM) platform, including the canine eACTH and feline TSH assays, in the first quarter of 2020.
This suggested the likelihood that the ECi TSH assay was subject to the same interferences as that of the Roche platform.
Clinical utility of sensitive TSH assays. Thyroid Today.
TSH assay: A blood sample was drawn in the non-fasting state and allowed to clot; aliquots were frozen at -80 [degrees] C Celsius until assay.
Recognize assays used to diagnose thyroid disease and the sensitivity for TSH assays.
Although the TSH assay is the most reliable screening test for thyroid dysfunction of either type, "it's important to remember that it's not perfect," and that poorly controlled diabetes can result in "inappropriately low" serum TSH concentrations, she said.
Take, for example, a TSH assay with the following characteristics: the normal range is 0.3 to 4.0 [mu]U/mL; the median TSH is 0.9 [mu]U/mL; 99% of thyrotoxic sera fall below 0.05 [mu]U/mL; the functional sensitivity is 0.03 [mu]U/mL; values above 4.0 [mu]U/mL are suspect for hypothyroidism, but TSH values less than 10[mu]U/mL are seldom associated with clinical hypothyroidism.
Principle: (Sandwich principle) The TSH assay employs monoclonal antibody specifically directed against human TSH.
This extended the clinical applications for the TSH assay to cover the full spectrum of thyroid disease.
This points to a general problem of estimating the functional sensitivity of a TSH assay and the definition of a third-generation assay (5) (limit of quantification <0.02 mIU/L with a maximum [CV.sub.t] of 20%).
Other less common causes include antibody interference in the [FT.sub.4] assay causing falsely increased [FT.sub.4], thyroid hormone resistance syndromes, TSH-secreting pituitary adenoma, familial dysalbuminemic hyperthyroxinemia, amiodarone therapy, and primary hyperthyroidism with antibody interference in the TSH assay causing falsely increased TSH results.