Laboratory Analysis of Free Thyroxine (FT₄)in Your Chemistry Laboratory Is

question 4

Multiple Choice

Laboratory analysis of free thyroxine (fT₄) in your chemistry laboratory is performed with a conventional fluorometric analyzer,which uses a laser light as the excitation source.You have received a sample from an individual known to have a very elevated fT₄ level.For the sample's value to be within linear range of the assay,you dilute the sample by a factor of 10 and proceed with the analysis.Upon reviewing the results,you note that the value of the diluted sample is reported as "none detected." What is the likely reason for this result?

• A) Hormones cannot be assayed using fluorometry because they will produce concentration quenching.
• B) The dilution of the sample has lowered produced photobleaching by the intense light source and photodecomposition of the analyte.
• C) Unwanted background fluorescence due to elevated protein hormone has produced a false-negative result.
• D) High intensity light emission can lead to pulse pileup in photomultiplier tubes,leading to an underestimation of the true light emission intensity.

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