Performance Evaluation of the VIDAS® D-Dimer Exclusion™ II Assay and the Beckman Coulter D-Dimer Assay.

BACKGROUND: The breakdown of fibrinogen and fibrin during the process of fibrinolysis creates D-dimer. A D-dimer analysis is crucial for the diagnosis of pulmonary embolism, deep vein thrombosis, and disseminated intravascular coagulation. The aim of this study is to evaluate the validity of two different D-dimer assays. METHODS: To analyze the D-dimer, venous blood taken in a vacuette containing 3.2% sodium citrate was used. Peripheral whole blood specimens were collected from 89 subjects, and plasma was separated from these specimens. VIDAS® D-dimer Exclusion™ II and the Beckman Coulter D-dimer assays were used for the quantitative detection of D-dimer levels. The analytical performance of the two different D-dimer assays was compared. RESULTS: The plasma values of D-dimer ranged from 89.2 to 7,452.9 ng/mL (FEU) when tested on the VIDAS® platform and from 20 to 7,770 ng/mL (FEU) when tested on the Beckman Coulter platform. Our results showed that the agreement between the two methods was acceptable and Pearson's correlation coefficient (r) was 0.93 (p < 0.001). CONCLUSIONS: A high correlation exists between quantitative D-dimer measurements conducted with the VIDAS® D-dimer Exclusion™ II and the Beckman Coulter D-dimer assays.

Evaluation of Friedewald's Formula for Plasma LDL-Cholesterol Estimation.

BACKGROUND: Low-density lipoprotein cholesterol (LDL-C) can contribute to atherosclerosis if it is oxidized within the walls of arteries. Therefore, LDL-C plays an important role in cardiovascular disease risk assessment and prevention. The current study aims to evaluate the validity of Friedewald's formula in the Taiwanese population. METHODS: In this analytical cross-sectional study, a data set containing 31,729 results was used and lipid profiles of all samples were measured using the Beckman Coulter AU680 clinical chemistry analyzer. This study was conducted from September 2016 to August 2019. RESULTS: The agreement between the direct and calculated LDL-C was significant with Pearson's correlation coefficient (r) of 0.904 (p < 0.001). Mean LDL-C levels were 99.3 ± 32.8 mg/dL and 95.3 ± 37.6 mg/dL for direct and calculated LDC-C, respectively. CONCLUSIONS: Good agreement was observed between direct and calculated LDC-C. Therefore, it can be concluded that Friedewald's formula is applicable in LDL-C estimation when the direct method is not affordable.

Interference of Blood Glucose Testing by an Increase in Serum IgM Levels.

BACKGROUND: An absurd result of plasma glucose test caused by increased serum IgM levels. METHODS: Serum immunoglobulin levels are determined by using an immunoturbidimetric assay. Additionally, serial dilutions were performed to assess the absurd results. RESULTS: Our results showed that an increase in serum IgM levels induces errors in the measurement of the plasma glucose level. CONCLUSIONS: This study simply presents a message that both medical technologists and physicians need to be aware of this because improper results of blood glucose levels may result in aggressive and invasive patient management. Additionally, physicians may be led to wrong interpretation due to false levels of glucose. In fact, we do not know how often this situation accidentally occurs in the laboratory. Therefore, all medical technologists must stay alert to absurd and unusual test results and reconfirm the reason for an absurd result.