Mass Spectrometry Selectivity, Specifically

[摘要] “A mass spectrometer is a sensitive and specific instrument.” In some form or another, this is often the label applied to the platform by all manner of professions (chemists, physicists, biologists, physicians, clinicians, and laboratorians, novice and expert alike). This is a view of mass spectrometry (MS) through rose-colored glasses. It should be properly said that MS can be sensitive and specific, but not without due consideration for the measurement to be performed. In clinical laboratories, this measurement is the extraction, detection, and often, quantification of a compound of interest from a biological matrix. Note the last 2 words—biological matrix. It would be difficult to encapsulate the totality of frustration in MS users when confronted with the truth of “biological matrix.” And that truth is that a biological matrix is an ever-changing, inherently deceptive preanalytical variable beyond the control of scientific experimentation. All because of the P's.These are not the P's used in significance, or the first initial of 3.1415…. These P's have given rise to vaccinations for disease and antibiotics, as well as new viruses and antibiotic resistance. These P's are the foundation for immunoassays, as well as their source of error. These P's are, as literally as the term can be used, the raison d'être. They are Plasticity and Promiscuity.Plasticity is the ability of an organism to change phenotype in relation to varying conditions (1). Most previous uses define this change in regard to the external environment, but let us appreciate that change occurs internal to an organism as well (2). A runny nose is not a persistent physical attribute, but one that appears in response to both external stimuli (allergens) and intraorganism inducements (rhinovirus infection). Plasticity does not occur just at the organism level, but also at the molecular level. Changes in production of molecules …

[学科分类] 过敏症与临床免疫学