Table of Contents
The level of D-dimer has essential value in the serological diagnosis and Clinical Pathology Research of some diseases:studies have shown that D-dimer levels are significantly correlated with the differential diagnosis and clinicopathological features of breast cancer. And D-dimer is involved in coagulation activation and has been applied to diagnose venous thromboembolism (VTE). In addition, D-dimer levels increase in several kinds of cancer and correlate with poor prognosis and resistance to treatment. Sysmex CS-5100 automatic coagulation analyzer is a commonly used instrument in clinical pathology laboratories and can detect D-dimer content.
The relationship between the level of D-dimer and clinicopathological features
D-dimer is a soluble degradation product of cross-linked fibrin. It is commonly used to diagnose disseminated intravascular coagulation and thromboembolic disorders such as deep vein thrombosis (DVT) and pulmonary embolism (PE).Compared to other assays employing methods such as whole blood agglutination assay and ELISA, immunofluorescence or latex agglutination assays have become the most widely used methods for examining D-dimer due to their combination of convenience and relatively high advantages of sensitivity and specificity.
Much literature has shown that tumors can cause the concentration of D-dimer to increase in patients, and it can be used as a criterion for staging and prognosis.However, many researchers believe heterophilic antibodies may interfere with interpreting D-dimer tests. Other factors may also interfere with the results of coagulation tests, such as heart failure, infection, and the use of anticoagulant drugs.
Activation of coagulation and fibrinolysis is known to be frequently associated with malignancy, although the mechanism involved has not been fully clarified. The extent of such activation has been reported to correlate with tumor stage and prognosis in some malignancies, including colorectal cancer. D-dimer is a stable end-product of fibrin degradation, and levels of D-dimer are elevated by enhanced fibrin formation and fibrinolysis. It is a marker of the hypercoagulable stage. D-dimer levels are elevated in the plasma of various solid tumor patients. Some Research scientists evaluated the clinical significance of D-dimer levels and the relationship between plasma D-dimer levels and clinicopathological outcomes before and after surgery for colorectal cancer.
The conclusion found that Hypercoagulation and higher fibrinolytic activities occur in patients with colorectal cancer. The operative trauma could enhance fibrinolysis in patients with colorectal cancer. The measurement of preoperative D-dimer levels helps predict lymph node metastasis and the stage of colorectal cancer[4].
Clinicopathological Study Case
An 82-year-old woman was admitted to the hospital with a diagnosis of chronic heart failure. The test results showed that the D-dimer level was significantly elevated, which exceeded the qualified range of the Sysmex CS-5100 System™ automatic coagulation analyzer (> 100 mg/L). Patient characteristics and diseases such as aging; pregnancy; recent injury, surgery, or trauma; sepsis; cancer; and some liver or kidney diseases are also known to be associated with elevated D-dimer levels.
To rule out the influence of any of these comorbidities, scientists confirmed her medical history and performed a battery of serum tests. Considering her age and sex, the results of all examinations were within the normal reference range, and her relevant medical history was adverse.
In this case, repeated tests by the scientists confirmed that her D-dimer levels were significantly above the acceptable range. However, the patient had no relevant clinical symptoms or radiologic evidence of abnormalities in mean FDP values and other coagulation parameters indicative of thrombus formation, thus raising the possibility of interference.
As a first step in the diagnostic workshop, samples were manually diluted to different levels and then calibrated using the Innovaccer D-dimer assay. Patient results showed a weak linear response (R2 at dilution = 0.9186), whereas parallel samples were similar to the standard curve (R2 = 0.9997, Panel A). Dilution is a method used to verify interference when test results are very high. However, a weak linear response or nonlinear response may lead to false confirmation of suspected interference.
As shown in Figure B, the latex agglutination assay uses latex beads coated with a D-dimer-specific antibody, and agglutination is detected by turbidity in the presence of D-dimer, latex beads, and a heterophile antibody:
The scientists performed additional experiments to confirm the difference, including sample dilution, reanalysis by alternative methods, and sample treatment by blocking specific heterophile antibodies. A significant disappearance of elevated D-dimer values was observed in the samples following these methods (4.49, 9.42, 9.06, and 12.58 mg/L, respectively). This confirms the presence of heterophilic antibodies in this case.
Sysmex CS-5100 Automatic Coagulation Analyzer
In modern laboratories, most analyzers used in clinical chemistry, hematology, and hemostasis are automated to reduce turnaround time (TAT) (especially for emergency room and intensive care unit samples) and maximize Any new coagulation analyzers must be compatible with the standard parameters used to measure (PT, PTT, fibrinogen, antithrombin, D-dimer) to minimize the personnel required to operate them. Especially in laboratories associated with blood transfusion services, precise measurement of mono factorial activity is necessary to obtain all official licenses required. The system should also perform more specific assays, such as protein C, S, and VWD.
In the above case, the D-dimer parameter of citrated plasma samples was evaluated using the Sysmex CS-5100 System (Siemens Healthcare Diagnostics, Erlangen, Germany), a particle-enhanced immunoturbidimetric assay with sensitivity and Specificities were 97% and 91%, respectively. Her D-dimer test was repeated over the next two weeks and consistently had high values (>100 mg/L) using the same test method, ruling out analytical errors such as inaccurate pipetting, improper washing Sufficient, tracer accumulation, or other contamination. Her FDP also continues to remain moderately elevated.
The Sysmex CS-5100 system is a fully automated, computer-interfaced coagulation analyzer for in vitro diagnostics. The analyzer has 36 culture wells and 20 measurement channels. Sysmex systems are capable of coagulation, chromogenic, and immunological testing. The absorbance measurement unit uses halogen lamps with 340, 405, 575, 660, and 800 nm wavelengths.
The analyzer accommodates 10 sample racks with ten samples each, enabling the simultaneous mixing of primary tubes from different manufacturers on the same rack. Use the rack system to store up to 40 reagents on board, and all are cooled at ten °C ±2°C. Five additional positions are dedicated to buffer or wash solutions at ambient temperature.
In addition, five STAT positions can be loaded continuously; the analyzer will immediately start measuring the sample. Barcode readers identify samples, controls, and reagents. Since control plasma can be included in the reagent area, control measurements can be performed at any time, e.g., when using new reagent bottles. Controls can also be run from 4 mL cups loaded on sample racks to avoid reducing the number of available reagent positions.
Cuvettes (up to 1000) and samples can be loaded continuously during the measurement. If reagent replacement is required, the system will be shut down at the next practicable time. Advanced software algorithms record, monitor and examine reaction kinetics to determine correct clotting times. In addition, the system provides an overview of all loaded reagents, showing the number of tests remaining and the time since the reagents were uploaded to the analyzer. Connection to the system manager is optional.
The Medicilon Clinical Pathology Laboratory is a GLP medical testing laboratory affiliated with the Pathology Research Department; the laboratory is mainly responsible for testing various animal biochemistry, hematology, coagulation, urinalysis, urine sediment microscopy, lymphocyte typing, Hemolysis in vitro, microscopic examination of bone marrow smear, and animal physical examination provide an objective and scientific basis for animal experiments. Since 2018, the laboratory has participated in the external quality assessment of the Shanghai Clinical Laboratory Center. It has passed all items for four consecutive years and has obtained the certificate issued by the Shanghai Clinical Laboratory Center.
References:
[1] Han-Xiao Sun, Hong Ge, et al. Clinical laboratory investigation of a patient with an extremely high D-dimer level: A case report. World J Clin Cases. 2020 Aug 26;8(16):3560-3566. doi: 10.12998/wjcc.v8.i16.3560.
[2] G L Salvagno, G Lippi, et al. Analytical comparison of AxSYM, HemosIL DD HS and Innovance D-dimer immunoassays with the Vidas D-dimer. Int J Lab Hematol. 2009 Aug;31(4):475-7. doi: 10.1111/j.1751-553X.2008.01077.
[3] T. Flieder, T. Gripp, et al. The Sysmex CS-5100 coagulation analyzer offers comparable analytical performance and excellent throughput capabilities. Pract Lab Med. 2016 Dec 1; 6: 38–47. Published online 2016 Sep 21. doi: 10.1016/j.plabm.2016.09.002.
[4] Gang Xu, Ya-Li Zhang, and Wen Huang. Relationship between plasma D-dimer levels and clinicopathologic parameters in resectable colorectal cancer patients. World J Gastroenterol. 2004 Mar 15; 10(6): 922–923. doi: 10.3748/wjg.v10.i6.922.
