Other Diagnostic Uses

Hospital and commercial diagnostic testing laboratories rely on monoclonal antibody tests to measure the amounts of specific proteins, hormones, or drugs in blood. Monoclonal antibodies tagged to fluorescent dyes are also used with lasers to determine the kind of tumor a patient has, to track the number of tumor cells, and to monitor the level of immune system cells. The CD4 count test, important to patients with HIV infection, uses monoclonal antibodies and a laser-driven device that checks cell by cell for the CD4 protein, the marker for the critical immune system cell. The same technology and a set of antibodies to immune system cell proteins are used to diagnose children suspected of having inherited an immune system deficiency. 

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Other diagnostic uses of aerosols are, for example, measurements of muco-ciliaiy fransport and airway permeability, the latter with pentetie aeid (diethylene-triamine pentaacetic acid DTP A) clearance. 

The process of classification in terms of each method of discrimination among diagnostic entities rests on two assumptions. First, the diagnostic entity or subtype is presumed to be a mental disorder. Second, the diagnostic entity is presumed to be discriminable from other mental disorders on some basis. Evaluation of this first assumption returns us to the earlier discussion of what constitutes a mental illness, so we do not need to consider this further. The second assumption raises a new question relevant to classification. Is this condition significantly unique from all other diagnostic categories An answer to this question should be empirically based, but the type of answer received may depend on the methods used to obtain the answer. Next, we consider different methods of classification. 

The indication to perform an accurate assessment of disease extension depends on the clinical need. In patients diagnosed at an advanced stage of disease with no therapeutic options, the results of diagnostic US provide enough information and no other techniques are necessary. In those individuals in whom a treatment decision has to be taken, in contrast, accurate staging is necessary to determine the best treatment method. In these patients, tumor staging should include the assessment of number, size, location, and characteristics of the tumor nodules tumor vascular invasion and nodal and extrahepatic metastases. 

Quest Diagnostics have established a routine system for testosterone, which has now replaced their other methods of analysis (Goldman et al., poster, US Endocrine Society meeting, San Diego, 2005). The analysis is carried out on a Thermofinnigan TSQ Quantum Ultra operated with an APCI source in the positive-ion mode. They use two transitions, 289—>109 and 289—>97, for the analyte and 294—>112 and 294—> 99 for the 2H5-labeled internal standard. On-line extraction and short retention times allow them to assay several thousand samples per month per instrument, making it cost-effective in spite of the high cost of instrumentation. 

Shapes or profiles of spectral lines are often very important for obtaining information about the physical system under observation. Thus a spectral profile can tell us the state of a stellar atmosphere, or it can be used as diagnostic for a plasma. The line shape of an NMR spectrum may disclose the internal motion of nuclei in a molecular system. The information thus obtained is admittedly not extremely detailed, but it may be very useful particularly when combined with other information, and often it is the only data available. 

Diagnostic plots can only tell us about the deficiencies of the model and not about its adequacy unless we compare it to the same type of plots based on other contending models. In practice, if we cannot see any problems in our battery of diagnostic plots, then we assume the model is without substantive error. Therefore, it is important to use a multitude of graphs to inspect as many aspects as possible of the model. However, we need to be careful because a diagnostic plot may appear suboptimal even if the model is adequate. There are basically two reasons for this phenomenon. 

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