Candidate reference method for total thyroxine

Candidate reference method for total thyroxine
Candidate reference method for total thyroxine

Routine clinical tests for hormones are generally immunoassay-based, and intercomparison studies have revealed problems in precision, accuracy, and specificity for some of these assays, particularly at low hormone concentrations. NIST has developed reference measurement procedures and a new reference material, SRM 971 Hormones in Human Serum, to address the need for improved accuracy of routine.Similar limitations have been observed in routine clinical assays for other hormones as well. Improving the accuracy of clinical assays for hormones will improve diagnoses and result in earlier treatments. The new reference methods and SRM 971 Hormones in Human Serum will help achieve this goal and will also provide higher-order reference systems for traceability.

Mar 29, 2009. The new reference methods and SRM 971 Hormones in Human. additional certified values will be added for estradiol-17, thyroxine,. Spectrometry. Candidate Reference Method for total Testosterone in Human Serum.BACKGROUND : There is a need for a critically evaluated reference method for thyroxine to provide an accuracy base to which routine methods can be traceable. We describe a candidate reference method involving isotope-dilution coupled with liquid chromatography/mass spectrometry.

Major Accomplishments: Reference measurement procedures have been developed for cortisol, estradiol-17, progesterone, testosterone, thyroxine (T4 and triiodothyronine (T3) A Standard Reference Material for hormones in human serum has been developed (SRM 971).METHODS : An isotopically labeled internal standard, thyroxine-d(5 was added to serum, followed by equilibration, protein precipitation, and ethyl acetate and solid-phase extractions to prepare samples for liquid chromatography-mass spectrometry electrospray ionization (LC/MS-ESI) analysis.

Candidate reference method for total thyroxine in human serum: use of isotope- dilution liquid chromatography-mass spectrometry with electrospray ionization.Function Tests (WG-STFT ). spectrometry (ID-LC/tandem MS) procedure for total. Candidate reference measurement procedure for free thyroxine in serum.

Both T3 and rT3, triiodo analogues of T4, are mainly produced by peripheral. Candidate Reference Method for Total Thyroxine in Human Serum: Use of.Chem., (2004). Tai, S.S-C. and Welch, M.J., "Development and Evaluation of a Candidate Reference Method for the Determination of Total Cortisol in Human Serum Using ID-LC/MS and LC/MS/MS Anal. Chem., (2004).

End Date: Ongoing Lead Organizational Unit: mml Customers/Contributors/Collaborators: Related Programs and Projects: Associated Products: SRM 971 Hormones in Human Serum. Associated Publications: Julianne Cook Botelho, Christopher Shacklady, Hans C Cooper, Susan S-C Tai, Katleen Van Uytfanghe, Linda M Thienpont and Hubert W Vesper.Bioanal. Chem., 388:108794 (2007). Tai, S.S.-C., Xu, B., and Welch, M.J., "Development and Evaluation of a Candidate Reference Measurement Procedure for the Determination of Progesterone in Human Serum Using ID-LC/MS/MS Anal.

Thyroxine during lithium therapy necessary

The results from the LC/MS-ESI method were within 1 SD of the composite means from many routine clinical methods, although it appears that the clinical method means may be biased high by 4-5 microg/L across the concentrations.Use of this reference method as an accuracy base may reduce the apparent biases in routine methods along with the high interlaboratory imprecision.

The role of mass spectrometry in the measurement of total T4 and T3 has been recently. Candidate reference method for total thyroxine in serum: use of.It is often called the "stress hormone" because it is secreted at higher levels in response to stress. Prolonged elevation of cortisol levels in the bloodstream can have negative effects on thyroid function, metabolism, and immune function.

Description: Steroid hormones (cortisol, progesterone, estradiol-17, testosterone) and thyroid hormones (thyroxine, triiodothyronine) serve an essential function by regulating gene transcription. Cortisol is a steroid hormone that is produced by the adrenal gland.Samples of frozen serum pools were prepared and measured in three separate sets. RESULTS : Within-set CVs were. The correlation coefficients of all linear regression lines (measured intensity ratios vs mass ratios) were.

Summary: Hormones are chemical messengers that regulate many life functions, and deviations from normal levels can indicate serious health problems. Measurement of levels of steroid and/or thyroid hormones in serum can be beneficial in diagnosing and monitoring a number of diseases.Isotope Dilution Liquid Chromatography Tandem Mass Spectrometry Candidate Reference Method for total Testosterone in Human Serum. Clin Chem 59, 372-380 (2013). Tai, S.S-C., Xu B., Welch M.J., and Phinney K.W., "Development and evaluation of a candidatereference measurement procedure for the determination of testosterone in human serum using isotope dilution liquid chromatography/tandem mass spectrometry Anal.

Additional Technical Details: SRM 971 Hormones in Human Serum consists of two serum pools, one from normal adult males, and one from normal, premenopausal adult females. Both pools are unfortified. In order to value assign the analytes of interest in SRM 971, a suite of isotope dilution liquid chromatography-mass spectrometry (LC/MS and LC-MS/MS) methods were.Measurement of cortisol in serum can be used to diagnose problems in the adrenal or pituitary gland, as well as stress-related disorders. Previous work has indicated that routine clinical measurements may significantly overestimate the cortisol levels present in serum, making accurate diagnosis of cortisol-related disorders difficult.

Nov 18, 2004. Methods: Four candidate RMLs (cRMLs) developed/implemented variants of a candidate reference measurement procedure (cRMP) based on.Trimester-specific reference intervals for thyroxine and triiodothyronine in pregnancy. Candidate reference method for total thyroxine in human serum: use of.

Tai, S.S-C., Sniegoski, L.T., and Welch, M.J., "Determination of Thyroxine in Human Serum by ID-LC/MS with Electrospray Ionization Clin. Chem., (2002).Positive- and negative-ion measurements agreed with a mean difference of 0.45 at three concentrations (50, 110, and 168 microg/L). The detection limits (at a signal-to-noise ratio of approximately 3 to 5) were 30 and 20 pg for positive and negative ions, respectively.

M H ions at m/z 778 and 783 for thyroxine and its labeled internal standard were monitored for positive ions and M - H(-) ions at m/z 776 and 781 for negative ions.These methods are recognized by the Joint Committee for Traceability in Laboratory Medicine (JCTLM ) as reference measurement procedures (RMPs) of a higher-order. Certified values have been assigned for cortisol, progesterone, and testosterone in SRM 971, and additional certified values will be added for estradiol-17, thyroxine, and triiodothyronine.

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