Clinical specificity

Clearly, bDNA is more sensitive than LH, HC, and in-house membrane hybridization assays, but its relatively high LOQ is not optimal for detecting lower titers associated with active liver disease. There have been no differences in clinical specificity among the HBV DNA quantitation methods reported. 

Compared with older methods, MS/MS is a more sensitive technique, offers greater accuracy and precision,has higher clinical specificity and sensitivity, and measures multiple analytes. It has been described as a revolutionary technique for disease detection. 

The lack of specificity of total AMY measurement has led to the interest in the direct measurement of P-AMY instead of total enzyme activity for the differential diagnosis of patients with acute abdominal pain. By applying the best decision limit (i.e., an activity equal to threefold the upper reference limit), the clinical specificity of P-AMY for the diagnosis of acute pancreatitis was greater than 90%. The... 

LPS measurement on serum is used to diagnose acute pancreatitis. The clinical sensitivity is 80% to 100% depending upon the selected diagnostic cutoff. The clinical specificity is 80% to 100% depending upon the mix of patient population studied. After an attack of acute pancreatitis, serum LPS activity increases within 4 to 8 hours, peaks at about 24 hours, and decreases within 8 to 14 days. Concentrations often remain elevated longer than those of AMY do. Elevations between 2 and 50 times the upper reference limit have been reported. The increase in serum LPS activity is not necessarily proportional to the severity of the attack. ... 

Interpretation For optimum clinical specificity, a positive result highly suggestive of a pheochromocytoma includes an elevation of norepinephrine and normetanephrine at 3 hours and a failure to suppress norepinephrine more than 50% and normetanephrine more than 40 % below the baseline plasma level. 

Cummins and co-workers were the first to develop a radioimmunoassay to measure cTnl that used polyclonal anti-cTnl antibodies. Although the assay showed approximately 2% cross-reactivity with skeletal Tnl, it stiU had excellent clinical specificity for cardiac muscle injury. The assay was never automated or developed for commercial use. The first monoclonal ELISA, anti-cTnl antibody-based immunoassay, was described by Bodor et al. This assay has less than 0.1% cross-reactivity with skeletal Tnl, but it was not suited for clinical use because of the lengthy assay time. Over the past 15 years, numerous manufacturers have described the development of monoclonal antibody-based diagnostic immunoassays for the measurement of cTnl in serum. Assay times range from 5 to 30 minutes. As shown in Table 44-1, over a dozen assays have been approved by the FDA for patient testing within the United States on central laboratory and POCT platforms. In addition to these quan-... 

While this chapter has reviewed the current recommendation for bioraarker testing predicated on cardiac troponin at the 99th percentile or 10% CV limits, different physician groups may adhere to different principles regarding the sensitivity and specificity of a biomarker (cardiac troponin). In emergency medicine, the ED physician desires a test that win provide high specificity and not miss any possible MI patients. However, with the highly improved cardiac troponin assays in the marketplace, the 100% sensitivity that troponin assays offer demonstrates a clinical specificity of... 

The impact of multiple analytes for amino acids in NBS cannot be overestimated. By measuring both Phe and Tyr, the detection of PKU was improved without the need for separate analyses. Comparison to other methods demonstrated that MS/MS improved selectivity and sensitivity (both analytically and clinically) by not only measuring two single metabolites simultaneously, Phe and Tyr, but by the ability to express the concentration of these two metabolites as a molar ratio, Phe Tyr. As shown in a subsequent publication, Phe Tyr could reduce false results and improve clinical specificity [3]. Furthermore, calculation of ratios of Phe to other amino acids such as leucine (Leu) enabled differentiation of a generalized elevation of amino acids due to intravenous (IV) nutrition (TPN, total parenteral nutrition) from PKU [13]. 

Lack of clinical specificity - need for localisation in order to increase the site-specificity of the dmg. 

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