Verification of Claimed Limit of Detection in Molecular Diagnostics.

Background: Limit of detection (LOD) is an important performance characteristic of clinical laboratory tests. Verification, as recommended by the CLSI EP17-A2 guideline, is done by testing a sample with a claimed LOD concentration. Claimed LOD is verified if the 95% CI for the population proportion, calculated from observed proportion of positive results, contains the expected detection rate of 95% (CLSI EP17-A2; Clin Chem 2004;50:732-40).

Evolution in the sensitivity of quantitative HIV-1 viral load tests.

Significant advancements in molecular diagnostics have been made since the inception and application of PCR-based technologies in clinical diagnostic laboratories and the management of HIV-1 infected patients. More recently, real-time PCR has improved the overall performance of assays used for detecting and quantifying HIV-1 RNA viral load in patients undergoing antiretroviral treatment. The effects of these changes and the interpretations of the HIV-1 viral load results are discussed in this review in the context of the different assays used, the viral dynamics of the HIV-1 virus, and the recent changes to HIV-1 treatment guidelines.

Evaluation of assigned-value uncertainty for complex calibrator value assignment processes: a prealbumin example.

Background: Errors of calibrator-assigned values lead to errors in the testing of patient samples. The ability to estimate the uncertainties of calibrator-assigned values and other variables minimizes errors in testing processes. International Organization of Standardization guidelines provide simple equations for the estimation of calibrator uncertainty with simple value-assignment processes, but other methods are needed to estimate uncertainty in complex processes.