The diagnostic evaluation of pulmonary embolism

Challenges, Recommendations, and Epidemiology of Pulmonary Embolism in India: A Narrative Review

An embolized clot that travels to the lungs from the legs or, less commonly, other parts of the body (known as deep vein thrombosis or DVT) causes pulmonary embolism (PE), which is characterized by obstruction of blood flow to the pulmonary artery. As PE has the propensity to masquerade as various illnesses affecting both the cardiovascular (CV) and the respiratory system, it is crucial to identify PE at the earliest. Appropriate diagnosis of PE may lead to earlier treatment and improved patient outcomes. While pulmonary angiography remains the established gold standard for diagnosing PE, the contemporary standard of care for this condition is the computed tomography pulmonary angiogram (CTPA). Anticoagulation therapy is the fundamental strategy for managing PE, with the forefront of treatment being the use of novel and upcoming oral anticoagulants known as non-vitamin K antagonist oral anticoagulants (NOACs). The NOACs provide a practical single-drug treatment strategy, which does not hinder the patient's lifestyle and domestic responsibilities. Although PE may be fatal, early detection may lead to effective management. Despite that, mortality and morbidity associated with PE are very high in India. The awareness among Indian healthcare professionals about PE should be improved, and unified pan-country diagnostic and management guidelines should be formulated to tackle the country's PE burden.

No need for a gold-standard test: on the mining of diagnostic test performance indices merely based on the distribution of the test value

BACKGROUND

Diagnostic tests are important in clinical medicine. To determine the test performance indices - test sensitivity, specificity, likelihood ratio, predictive values, etc. - the test results should be compared against a gold-standard test. Herein, a technique is presented through which the aforementioned indices can be computed merely based on the shape of the probability distribution of the test results, presuming an educated guess.

METHODS

We present the application of the technique to the probability distribution of hepatitis B surface antigen measured in a group of people in Shiraz, southern Iran. We assumed that the distribution had two latent subpopulations - one for those without the disease, and another for those with the disease. We used a nonlinear curve fitting technique to figure out the parameters of these two latent populations based on which we calculated the performance indices.

RESULTS

The model could explain > 99% of the variance observed. The results were in good agreement with those obtained from other studies.

CONCLUSION

We concluded that if we have an appropriate educated guess about the distributions of test results in the population with and without the disease, we may harvest the test performance indices merely based on the probability distribution of the test value without need for a gold standard. The method is particularly suitable for conditions where there is no gold standard or the gold standard is not readily available.