Prestandaundersökning av den patientnära analysmetoden Biosynex® D-dimer via jämförelse med den laborativa analysmetoden STA-Liatest® D-Di PLUS

Sammanfattning: The fibrinogen degradation product D-dimer is released in plasma during fibrinolysis. D-dimer analysis is mainly ordered for the exclusion of venous thromboembolism (VTE) in combination with a pre-test probability (PTP) score. D-dimer below 0,5 mg/L fibrinogen equivalent units (FEU) and a low PTP rules out VTE. D-dimer analysis contributes to the reduction of invasive and expensive imaging analyses, such as ultrasound and computed tomography. The Blekinge region primary care used a qualitative D-dimer point of care test (POCT) whose performance the clinical chemistry of Blekinge hospital had no insight into. The aim of the study was to investigate whether the qualitative D-dimer POCT was an adequate complement to the quantitative method used in the hospital laboratory. Fifty patients, whose blood samples arrived the laboratory in tubes with sodium citrate- and ethylenediaminetetraacetic acid (EDTA) additives, were chosen for the study. Citrate plasma was analyzed with the D-dimer laboratory method. Plasma and whole blood were analyzed with the D-dimer POCT. Quantitative results were converted to qualitative based on the cutoff value 0,5 mg/L FEU. POCT performance was computed and compared with the manufacturer’s specified values. A potential difference between the methods was evaluated with a Chi-squared test. A survey was performed where open care units answered questions regarding D-dimer POCT. The POCT performance was slightly lower than the manufacturer’s specifications. No statistically significant difference was seen between the methods. However, there were several sources of error with the latter. Some open care units mentioned weak lines in the reading area due to blood interference.