Influence of mechanical hemolysis of blood on two D-dimer immunoassays

Abstract

Although there is broad information about the influence of spurious hemolysis on several laboratory tests, less is known on the bias produced on D-dimer testing. Four different pools were obtained from primary blood tubes, and each of them was divided into four aliquots. The first nonhemolyzed was centrifuged, the plasma was separated and then tested for hemolysis index and D-dimer. The second (hemolyzed aliquot A), third (hemolyzed aliquot B) and fourth (hemolyzed aliquot C) aliquots were mechanically hemolyzed by aspirating whole blood one, two and three times through a fine needle. The plasma was then separated and tested for hemolysis index and D-dimer. D-dimer was quantified by HemosIL AcuStar D-dimer and HemosIL D-dimer HS for ACL TOP. Undetectable hemolysis was present in aliquot nonhemolyzed (<0.5 g/l), whereas the concentration of cell-free hemoglobin significantly increased from hemolyzed aliquot A (5.5-7.0 g/l hemoglobin) to hemolyzed aliquot B (11.5 and 15.0 g/l hemoglobin) and hemolyzed aliquot C (20-22 g/l hemoglobin). The plasma concentration of D-dimer decreased from aliquots nonhemolyzed to hemolyzed aliquot C, achieving clinical significance fromhemolyzed aliquot A and hemolyzed aliquot B when measured with D-dimer HS for ACL TOP and AcuStar D-dimer, respectively. The decrease with AcuStar D-dimer was -5 ± 3% in hemolyzed aliquot A, -7 ± 3% in hemolyzed aliquot B, and -9 ± 3% in hemolyzed aliquot C, whereas the decrease with D-dimer HS for ACL TOP was -5 ± 3% in hemolyzed aliquot A, -8 ± 3% in hemolyzed aliquot B and -9 ± 3% in hemolyzed aliquot C. The similar trend towards decreasing values observed when measuring D-dimer with chemiluminescent and turbidimetric immmunoassays on four heterogeneous plasma pools suggest that the hemolysis interference is more likely to be biological than analytical. The modest bias observed in samples with frank hemolysis (i.e. cell-free hemoglobin of 11.5 g/l) confirms that both methods are robust against this type of interference, so that test results might be released in the majority of mildly hemolyzed samples.

Effects of haemolysis, icterus and lipaemia on coagulation tests as performed on Stago STA‐Compact‐Max analyser

“…The vast majority of haemolysed specimens detected in clinical laboratories are only mildly haemolytic (i.e. with cell-free haemoglobin < 0.6 g/L) [18]. In contrast to what has been described for fibrinogen measured in a grossly haemolysed plasma sample using a photo-optical detector, the fibrinogen level was not clinically significantly affected by haemolysis in our study [12].…”

Interference in Coagulation Testing: Focus on Spurious Hemolysis, Icterus, and Lipemia

“…In a subsequent study, we assessed the influence of mechanical hemolysis of anticoagulated blood on two different D-dimer immunoassays, the former based on an immunoturbidimetric technique (He-mosIL D-dimer HS for ACL TOP, Instrumentation Laboratory, Bedford, MA) and the latter on a chemiluminescent immunoassay (HemosIL AcuStar D-dimer, Instrumentation Laboratory). 55 It is noteworthy that a rather similar trend toward reduced values was observed with both methods on four different plasma pools, thus suggesting that the interference from hemolysis seems more biologic than analytical. In agreement with the previous investigation, the overall bias observed in samples with gross hemolysis (i.e., concentration of cell-free hemoglobin > 11.5 g/L) was modest, always lower than 10%, thus indicating that test results obtained in the vast majority of hemolyzed specimens might still be reliable for this parameter and thereby could be safely released to the clinicians.…”

D-dimer: Preanalytical, analytical, postanalytical variables, and clinical applications

“…In vitro hemolysis still represents one of the most frequent causes of preanalytical problems in clinical laboratories, with a prevalence ranging between 30-70% of all unsuitable specimens [22,[49][50][51][52]. Causes of hemolyzed samples could result from patient's characteristics or diseases (e.g.…”

“…However, a clinically significant variation (10%) was observed only above cell-free hemoglobin concentrations of 13.6 g/L (or final lysate concentration of %6.4%) [51,53]. Another study by the same authors evaluated the impact of mechanical hemolysis (syringe equipped with a fine needle (30 G, 0.3 Â 8 mm)) on two different D-dimer assays (HemosIL AcuStar V R (Werfen, USA) and HemosIL HS V R (Werfen, USA)) [49]. The D-dimer concentration measured with the HemosIL HS V R reached a clinically significant decrease (À5%) from a hemolysis index between 5.5-7.0 g/L of cell-free hemoglobin.…”