Clinical application of laboratory diagnosis: leukemia and DIC]

Plasma levels of molecular markers of hemostatic activation were investigated in 205 samples from patients with haematopoietic malignancies. These markers included thrombin/antithrombin III complex (TAT), D-dimer, plasmin/alpha 2plasmin inhibitor complex (PIC) and thrombomodulin (TM), and were assayed by EIA methods. Samples were divided into 4 groups according to the level of FDP: group A; FDP 10 greater than, group B; 10 less than or equal to less than 20 group C; 20 less than or equal to less than 40, and group D; less than 40. The mean level of each marker except TM increased in the order of group A, B, C and D. However, in many samples belonging to group A the plasma TAT or PIC levels and both were increased in spite of low FDP level. Furthermore, levels of TAT and PIC in several samples belonging to groups C and D were within the normal range. Also, the mean levels of each marker except TM increased in the order of 2, 3, 4, 5 and over 6 points in DIC score according to the criteria of DIC diagnosis by the research committee on DIC of the Ministry of Health and Welfare in Japan. Eight of the 11 samples (72.7%) obtained from cases with a DIC score of 3 points had high plasma levels of TAT, PIC and D-dimer. Plasma levels of these markers were increased after chemotherapy. These findings lead to the following conclusions: 1) FDP reflexed activation of coagulation and fibrinolysis, but 2) FDP was not more sensitive than TAT and PIC, and 3) the increase of FDP rarely resulted from fibrinogenolysis or non-plasmin mediated fibrinolysis. Furthermore, 4) TAT, D-dimer and PIC may serve as sensitive parameters of hemostatic activation in circulating blood and be valuable markers for early diagnosis of DIC.     

Diagnosis of disseminated intravascular coagulation. Role of D-dimer

Detection of the cross-linked fibrin degradation fragment, D-dimer, in patients at risk for disseminated intravascular coagulation (DIC) is strong evidence for the diagnosis. D-dimer confirms that both thrombin generation and plasmin generation have occurred. Patients at risk for DIC (58) and normal controls (7) were studied. Thirty-three patients had DIC--with fragment D-dimer identified in their serum by immunoblotting. Latex agglutination measurements of fibrin(ogen) degradation products (FDPs) and D-dimer were compared with immunoblotting in the detection of D-dimer. FDP measurement was extremely sensitive but not specific. D-dimer measurement was less sensitive but highly specific. Used in tandem, screening with FDP and confirming with D-dimer, sensitivity and specificity were maximized, rendering a predictive value of a confirmed FDP of 100% in this cohort. D-dimer is a valuable adjunct for the laboratory diagnosis of DIC but is most appropriately used as a confirmatory test for the very sensitive FDP test.     

Measurement of plasma fibrin D-dimer levels with the use of a monoclonal antibody coupled to latex beads

Recently, monoclonal antibody (DD-3B6) to fibrin D-dimer was prepared and coupled to latex beads to provide a specific test (Dimertest) for fibrinolysis. The purpose of this study was to evaluate the Dimertest assay as a clinical laboratory test for the measurement of plasma fibrin D-dimer derivatives. The Dimer-test assay specifically detected 2 micrograms/mL of purified fibrin D-dimer or fibrin D-dimer/fragment E complex added to afibrinogenemic plasma but did not detect 500 micrograms/mL of either fibrinogen fragments X, D, E, or 160 micrograms/mL cross-linked fibrinogen. The fibrin(ogen) degradation product (FDP) assays of American Dade or Wellcome Diagnostics detected 5.0 micrograms/mL of fibrin D-dimer and from 1 to 10 micrograms/mL of the other FDPs. Twenty-eight percent of 150 random plasma samples assayed from hospitalized patients were positive for fibrin D-dimer derivatives. Plasma samples from 152 patients suspected of having disseminated intravascular coagulation (DIC) were assayed for serum FDP (Wellcome Diagnostics) and plasma fibrin D-dimer derivatives. Samples from 69% of patients with serum FDP levels less than 10 micrograms/mL, and more than 90% of those with serum FDP levels greater than 10 micrograms/mL, were positive for fibrin D-dimer derivatives. Dimertest results were not modified by heparin, streptokinase, freeze-thawing, or clotting plasma. Serum fibrinogen-related antigens were immunoadsorbed from Dimer-test positive sera by anti-fibrinogen antibody and formalin-fixed Cowan I strain Staphylococcus aureus. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and protein blotting with the use of monoclonal antibody DD-3B6 demonstrated a protein band with similar mobility to purified D-dimer. The measurement of plasma fibrin D-dimer derivatives by the Dimertest assay is a rapid, sensitive, and specific laboratory test for fibrinolysis. The Dimertest assay has proven to be a useful addition to the clinical laboratory and should be helpful in the diagnosis and management of patients with diseases associated with fibrinolysis.     

Incidence and possible reasons for discordant results between positive FDP and negative D-dimer latex assays in clinical specimens.

In general, FDP and D-dimer values have a correlation in clinical conditions associated with disseminated intravascular coagulation(DIC) or coagulation activation. However, there are some patients with discordant results who demonstrate elevated FDP and negative D-dimer results by latex agglutination assays. The incidence and possible reasons for the discordance between FDP and D-dimer results were investigated through simultaneous measurements (n = 763) from clinical patients with suspected DIC or coagulation activation. 24.8% (189/763) of samples with elevated FDP were negative for D-dimer assays by the latex agglutination method. Further detailed analysis on randomly-selected discordant samples (n = 41) revealed that the most common reason for the discordance was the lower sensitivity of the semiquantitative latex agglutination method for D-dimer, compared with quantitative enzyme or other latex immunoassay. The other contributing factors to the discordance were accelerated fibrinogenolysis without secondary fibrinolysis, elevated soluble fibrin monomer and rheumatoid factor.     

Studies on the fragments of FDP in 4 patients with DIC]

We previously studied fibrinolysis and fibrinogenolysis by analyzing fragments of fibrin/fibrinogen degradation products (FDP) employing sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. In this report, we characterized the fragments of FDP in four patients with disseminated intravascular coagulation (DIC), that were caused by various diseases. In the patients suffering from acute lymphoblastic leukemia (case 1) and acute suppurative cholangitis (case 3), DD and DY/X fragments resulting from fibrinolysis accounted for the most part of the FDP fragments. In case 3, D fragments resulting from fibrinogenolysis were also observed to much less extent. In a DIC associated with acute myeloblastic leukemia (case 2), both fibrinolysis and fibrinogenolysis were increased and resulted in high levels of D, Y and DY/X fragments, concomitant with moderate levels of DD and high molecular weight (HMW) fragments in the patient's sera. The increased fibrinogenolysis in this case was attributed to accelerated activation of plasmin. In a DIC patient of case 4, who underwent an operation due to hepatocellular carcinoma, marked increase in DY/X and HMW fragments and slight increase in DD fragment were observed on the day of operation. Hyperfibrinolysis documented in case 4 was explained by both increased production of thrombin and moderately accelerated activation of plasmin. Both qualitative and quantitative changes in the fragments of FDP during the courses of treatment in two cases of DIC were also noted. In summary, each underlying disease expresses characteristic pattern of FDP fragments in DIC.     

Clinical significance of a new fibrinogen/fibrin degradation products(FDP) test using plasma samples for the diagnosis of fibrinogenolysis and fibrinolysis

Recently, a new fibrinogen/fibrin degradation products(FDP) test using monoclonal antibodies against FDP(LPIA FDP-P: FDP-P) has been developed, which is able to measure FDP directly in plasma. The objective of this study is to clarify clinical significance of the test in the diagnosis of fibrinogenolysis and fibrinolysis in comparison with a conventional FDP test using polyclonal antibodies against fibrinogen(FDP-S) and D-dimer test using monoclonal antibodies against D-dimer(D-D). The monoclonal antibodies used in FDP-P test was shown to recognize fragment X, Y and D1 derived from fibrinogen digested by urokinase, and was also to recognize XDP fragments, D-dimer and D derived from cross-linked fibrin digested by tissue plasminogen activator using SDS-PAGE and immunoblotting analysis. There was a good correlation of FDP levels between FDP-P test and FDP-S test. However, levels of FDP in both tests were discrepant in several samples. There was a tendency that the levels of FDP were higher in FDP-S test than in FDP-P test. Such discrepancy was suggesting that soluble fibrin monomer complex(FM) was recognized by the antibodies used in FDP-S test, but not recognized by the antibodies used in FDP-P test. There was also a good correlation of FDP levels between FDP-P test and D-D test. However, the levels of FDP in both tests were discrepant in several samples. The levels of FDP were higher in FDP-P test than in D-D test. These discrepant samples had lower levels of antiplasmin and higher levels of plasmin antiplasmin complex(PIC), and also showed XDP fragments, D-dimer, X, Y, and D1 by using SDS-PAGE. These observations suggest that D-D test measures only fibrinolytic fragments, while FDP-P test measures fibrinogenolytic fragments as well as fibrinolysis. In results, the FDP-P test was confirmed to be a useful tool to examine fibrinogenolysis as well as fibrinolysis more specifically than the conventional FDP test.     

Differentiation of fibrinolysis and fibrinogenolysis by analysis of FDP fragments]

We previously analysed the fragments of fibrin/fibrinogen degradation products (FDP) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) combined with immunoblotting. In this report, we studied the semi-quantitative analysis of fibrinolysis (degradation of cross-linked fibrin) and fibrinogenolysis (degradation of fibrinogen and/or unstable fibrin) of patients' samples by our method. In vitro study of FDP made it clear that an appearance of D fragment confirmed fibrinogenolysis and an appearance of DD fragment and/or high molecular weight fragments which have higher molecular weight than DY or X fragment confirmed fibrinolysis. In addition, a study with mixtures of various concentrations of fibrin degradation products (FbDP) and fibrinogen degradation products (FgDP) demonstrated a dose dependent intensity of band by immunoblot method. These results show that our method is favorable for the semi-quantitative analysis of fibrinolysis and fibrinogenolysis. We applied the method to 6 samples from patients with disseminated intravascular coagulation (DIC). Consequently, fibrinogenolysis was observed in all of 6 samples, in which fibrinogenolysis was more enhanced than fibrinolysis in one sample, and an equivalent degree of fibrinolysis and fibrinogenolysis were observed in 3 of 6 samples. Although our method was probably devoid of the ability to distinguish FgDP from degradation products of unstable fibrin, these findings indicate that fibrinogenolysis is, at any rate, enhanced in the majority of patients with DIC, besides fibrinolysis.     

Clinical evaluation of a test for plasma fibrin/fibrinogen degradation products (FDP) based on monoclonal anti-FDP antibody technology: an application for the scoring system of the disseminated intravascular coagulation (DIC) diagnostic criteria

Fibrin/fibrinogen degradation products(FDP) have been measured using serum samples which were specially prepared for the FDP test because of the usage of anti-human fibrinogen antibody for the assay. Since diagnostic criteria for DIC were established by the study group on thrombosis and hemostasis which is supported by the Japanese Ministry of Health and Welfare(JMHW), serum FDP assay have been used as standard methods to diagnose DIC in Japan. Recently, a reagent using an anti-human FDP monoclonal antibody was developed and this has enabled the use of plasma samples for FDP measurement. The comparability, especially of the DIC score, of a new assay, Latex test BL-2 P-FDP, using plasma samples with a conventional assay for serum was investigated. Two sets of DIC scores based on data from the two tests were compared and the correlation was high with 97.5% of the patients being diagnosed with the same DIC status. In four disease groups--DIC, thrombosis, leukemia and solid cancer--high comparability between the two tests was also shown and no significant difference was observed in the correlation coefficient and the slope coefficient between serum and plasma samples. To conclude, it is suggested that "Latex test BL-2 P-FDP" is applicable to the diagnostic criteria for DIC from JMHW without any difficulty.     

Fibrin monomer assay

Quantitative assay for fibrin monomer was done by use of a chromogenic substrate (S-2390, Coa set fibrin monomer). Samples from DIC prone patients with the underlying disease were assayed and classified into four groups. The pre DIC group showed higher FM values than the control with no laboratory coagulation abnormality, although the FDP . D-dimer showed no significant rise. FM assay is a useful marker for the detection of early coagulopathy in DIC. Administration of the AT III concentrate in the case of low level of plasma ATIII, thrombin . antithrombin complex I (TAT) caused a significant transient rise. The clinical course of DIC by TAT is often affected by the fluctuation of ATIII level in plasma, the usefulness of FM is that it reflects the real thrombin generation in DIC.     

Levels of tissue-type plasminogen activator and plasminogen activator inhibitor 1 in disseminated intravascular coagulation syndrome

Since disseminated intravascular coagulation (DIC) may directly reflect the abnormal regulation of the fibrinolytic system by endothelial cells, we have measured the levels of tissue-type plasminogen activator (t-PA), type 1 PA inhibitor (PAI-1) and t-PA . PAI-1 complex which is formed as a result of interaction on the two factors, in the plasma of patients with DIC (n = 51) and healthy controls (n = 42). Antigens of t-PA, PAI-1 and t-PA . PAI-1 complex were significantly increased in the DIC plasma (36.4 +/- 25.1, 106.8 +/- 54.7 and 46.6 +/- 34.5 ng/ml, respectively) compared with those in normal plasma (8.5 +/- 4.3, 54.4 +/- 21.2 and 8.6 +/- 3.5 ng/ml, respectively). The molar ratio of t-PA to PAI-1 was much higher in the DIC plasma (1:3) than in normal plasma (1:6), which caused enhancement of the whole fibrinolytic activity in the DIC plasma. These changes resulted in significant consumption of plasminogen, alpha 2-plasmin inhibitor (alpha 2-PI) and a significant increase of plasmin . alpha 2-PI complex (PPI) and D-dimer. These results suggest that t-PA and its specific inhibitor PAI-1 both of which are secreted from endothelial cells into blood, play an important role on the progress of DIC.     

Measurement of FDP-D-dimer in DIC and pre-DIC

We measured FDP-D-dimer value in disseminated intravascular coagulation (DIC), pre-DIC (within 7 days before onset of DIC) and suspected DIC (not completely satisfying the DIC criteria). The level of FDP in many patients with pre-DIC was normal, but the level of FDP-D-dimer in most patients with pre-DIC was increased. FDP was markedly increased one day before onset of DIC but FDP-D-dimer was increased 7 days before the onset. FDP was significantly higher in DIC than in pre-DIC, but it was not higher in pre-DIC than in suspected DIC. In patients with hematological malignancies, FDP-D-dimer was statistically higher in DIC than in pre-DIC and in pre-DIC than in suspected DIC, but in non-hematological malignancies, FDP-D-dimer was not significantly different among the 3 groups. The peak increase of FDP-D-dimer was noted at a DIC score of 7 or 8. The correlation of FDP-D-dimer with FDP was better in pre-DIC than in DIC, and the ratio of FDP-D-dimer to FDP was higher in pre-DIC. FDP-D-dimer was not correlated with fibrinopeptide A or B beta 15-42 in pre-DIC. It is speculated that pre-DIC is a hypercoagulable state and FDP-D-dimer may be useful to the diagnosis of pre-DIC.     

Heparin reduction with the use of cardiotomy suction is associated with hyperfibrinolysis during distal aortic perfusion with a heparin-coated semi-closed cardiopulmonary bypass system

We sought to elucidate the effects of different anticoagulation levels and the use of cardiotomy suction on the postoperative coagulatory and fibrinolytic systems in patients undergoing distal aortic perfusion using a fully heparin-coated (semi-)closed cardiopulmonary bypass (CPB) system incorporating a soft reservoir bag. Thirty-two patients were divided into two groups: those who underwent cardiotomy suction (S group, 18 patients) and those who did not (N group, 14 patients). We administered 1–2 mg/kg heparin in the S group, which achieved an activated clotting time (ACT) of 345 ± 71 s. In the N group, we administered 0.7–1 mg/kg heparin, which achieved an ACT of 297 ± 52 s. Data on platelet counts and serum levels of fibrinogen, antithrombin III, D-dimer, and fibrin degradation products (FDP) were collected, and factors influencing these variables were analyzed by multiple regression analysis. Both the patient group and the initial ACT level were independent factors influencing postoperative levels of FDP and D-dimer, whereas peak ACT level and the use of selective visceral/renal shunt/perfusion, but not the patient group, were independent factors influencing the postoperative platelet counts. In the S group, a significant inverse correlation was found between the ACT and levels of FDP or D-dimer, whereas no correlation was found in the N group. The use of cardiotomy suction was associated with elevated FDP and D-dimer levels even when a fully heparin-coated semi-closed CPB system was used. Lower ACT levels with the use of cardiotomy suction were associated with higher FDP and D-dimer levels, whereas such a relationship did not exist when cardiotomy suction was not used.     

Differentiation between fibrin degradation products and fibrinogen degradation products by using newly developed ELISAs

We should distinguish fibrin degradation products (FbDP) from fibrinogen degradation products (FgDP) in order to analyze fibrinolysis in vivo. We analyzed some disorders associated with hyperfibrinolytic states using ELISA for FbDP, FgDP and total fibrin (ogen) degradation products (TDP) (ORGANON TEKNIKA). Each ELISA was useful in terms of reproducibility and dilution linearity of plasma samples. There was no cross-reaction between FbDP and FgDP. The FgDP/FbDP ratio in normal individuals was 1.65. In patients with DIC, it was 0.43, with FgDP level being increased. These results suggest that fibrinolysis is enhanced in patients with DIC, but it is accompanied by fibrinogenolysis. On the other hand, the FgDP/FbDP ratio in patients given urokinase (UK) was 2.88. This suggests that fibrinogenolysis is enhanced in them. In our study, the FgDP/FbDP ratio increased as DIC improved. Thus, we can regard this as an index of therapeutic effects in patients with DIC. We conclude that these three ELISA are useful in analyzing disorders associated with hyperfibrinolytic states.     

Measurement of plasma D-dimer for diagnosis of deep venous thrombosis

Venography was performed on fifty-six patients suspected of having deep venous thrombosis (DVT) of the legs. The accuracy of the D-dimer measurement in plasma using two latex tests and an enzyme-linked immunosorbent assay (ELISA) was compared with that of usual determination of total fibrin(ogen) degradation products (FDPs) in serum with respect to the presence of DVT. The three D-dimer tests were clearly superior to the FDP assay, but only the ELISA could accurately rule out the diagnosis of DVT with a predictive value of 100% when plasma D-dimer level was less than 200 micrograms/L. However, this test cannot be used for positive diagnosis (false positive rate of 69%). Thus, plasma D-dimer measurement with ELISA allows identification of patients in whom further investigation by means of more specific tests (venography or plethysmography) is indicated in order to establish the diagnosis of DVT. In contrast to this, sensitivity of the two latex tests studied was low (60 and 76%, respectively), which makes them unsuitable for emergency screening. In addition, the potential of D-dimer dosage for diagnosis of DVT in hospitalized patients is hampered by the presence of associated conditions that are responsible for elevated plasma levels in most cases.     

Evaluation of an enzyme immunoassay for plasma thrombomodulin]

Thrombomodulin (TM) is an endothelial cell membrane glycoprotein which neutralizes thrombin clotting activity and accelerates thrombin-catalyzed activation of plasma protein C. Its role is considered to be very important to prevent thrombosis. Recently, TM has been found in circulating blood and the roles and the functions have been investigated. In this study, we evaluated the reliance and the clinical usefulness of a TM-measuring-kit by enzyme immunoassay (MGC-01-001: Mitsubishi Gas chemical company). Intraassay reproducibility test, dilution linearity test and in vitro recovery test was obtained satisfactory results. A correlation between plasma and serum on TM levels of healthy individuals was very good and the difference between them was not significant. Normal value of plasma TM levels was instituted 15.73 +/- 6.98 ng/ml by measuring 52 healthy adults. The difference between male and female was not significant. Plasma TM levels did not change significantly after venous occlusion test and on circadian fluctuation. Plasma TM levels in patients with occlusion test and on circadian fluctuation. Plasma TM levels in patients with disseminated intravascular coagulation (DIC) was 40.15 +/- 22.68 ng/ml (mean +/- SD, n = 14). It is significantly higher than the levels in healthy adults. However, the levels in patients with angina pectoris, acute myocardial infarction and aortic aneurysm were not significantly different from those of healthy adults. These findings suggest that the precision of this TM-measuring-kit is satisfactory and the measurement of plasma TM can be useful to diagnose of DIC.     

Criteria for diagnosing DIC

The differences between reagents of prothrombin time (PT), fibrinogen and fibrin and fibrinogen degradation products(FDP) were examined in patients with disseminated intravascular coagulation (DIC) and without DIC. The sensitivity of the PT ratio for DIC is lowered by the PT reagent with a high international sensitivity index, and the difference between PT reagents was marked. The sensitivity of PT-international normalized ratio (INR) for DIC was higher than that of the PT ratio and the difference between reagents in PT-INR was low. Though the difference between reagents for fibrinogen is slight, the usefulness in diagnosing DIC is also slight. Though the sensitivity of FDP for DIC was good, the difference between FDP reagents was marked. Therefore, standardization of PT and FDP seems to be necessary. Concordance of overt-DIC diagnostic criteria by the International Society of Thrombosis and Haemostasis (ISTH) and DIC diagnostic criteria of Japanese Ministry of Health and Welfare (JMHW) was about 70%, and overt-DIC diagnostic criteria of ISTH seemed to diagnose the typical type of DIC diagnosed by JMHW criteria. Finally, the diagnostic criteria of non-overt DIC are expected to become increasingly important.     

冠状动脉介入治疗患者tPA、D-二聚体、FDP检测的临床应用

目的:动态观察冠心病患者冠状动脉介入(PCI)治疗前后血浆组织纤溶酶原激活物(tPA)、D-二聚体(D-D)、纤维蛋白(原)降解产物(FDP)含量。方法:用ELISA对60例冠心病患者PCI术前、术后即刻和术后5天以及40例非手术对照组上述指标进行检测和比较;并进行门诊随访分析。结果:冠心病患者术前tPA含量明显低于对照组(P<0.05),D-D、FDP含量明显高于对照组(P<0.05);PCI术后即刻tPA较术前明显降低(P<0.01),术后5天回升至术前水平,但仍比对照组明显降低(P<0.01);D-D、FDP含量术后即刻较术前明显升高(P<0.01),术后5天下降至与术前无明显差异,但仍高于对照组(P<0.01)。门诊随访31例PCI术后疗效稳定患者tPA、D-D、FDP均与对照组无显著性差异(P>0.05)。结论:PCI可能造成冠心病患者血管内膜损伤而导致机体纤溶功能短期降低。     

Tissue plasminogen activator and plasminogen activator inhibitor-1 levels in patients with acute paraquat intoxication

To investigate the effects of reactive oxygen species (ROS) on tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) plasma levels, and their possible implications on clinical outcome, we measured tPA and PAI-1 levels in 101 patients with acute paraquat (PQ) intoxication. The control group consisted of patients who ingested non-PQ pesticides during the same period. tPA and PAI-1 levels were higher in the PQ group than in the controls. PQ levels were significantly correlated with ingested amount, timelag to hospital, tPA level, and hospitalization duration. tPA levels were correlated with PAI-1, fibrin degradation product (FDP), and D-dimer. D-dimer levels were lower in the PQ group than in the controls. Univariate analysis indicated the following significant determinants of death: age, ingested amount, PQ level, timelag to hospital, serum creatinine, lipase, pH, pCO(2), HCO(3) (-), WBC, FDP, PAI-1, and tPA. However, multivariate analysis indicated that only PQ level was significant independent factor predicting death. In conclusion, tPA and PAI-1 levels were higher, while D-dimer levels were lower in the PQ group than in the controls, implying that ROS stimulate tPA and PAI-1, but PAI-1 activity overrides tPA activity in this setting. Decreased fibrinolytic activity appears to be one of the clinical characteristics of acute PQ intoxication.     

Plasminogen activators in ovarian tumours.

Ovarian tumours obtained at laparotomy were histochemically examined for their local fibrinolytic activity, and simultaneous fibrin/fibrinogen degradation products (FDP) were determined in the serum. The fibrinolytic activity was confined mainly to vessels of both malignant and benign tumours. A very close correlation was demonstrated between the fibrinolytic activity and the vascularity of the sections. FDP were found in the serum in 13 of 14 patients with malignant tumours, but in none with benign tumours. The difference in occurrence of FDP in patients with malignant and benign tumours might be due to the invasive growth of the former with the entrance of thromboplastic substances, fibrinolytic activators or locally formed FDP into the bloodstream.     

30例D-二聚体假性增高的数据分析

目的探讨30例临床检测中血浆D-二聚体水平>FDP水平的原因及相关资料分析。方法收取临床检测过程中首次出现血浆D-二聚体水平>FDP水平的标本30例。分别用血浆D-二聚体检测试剂(STA-LIATEST D-DI和STA-LIATEST D-DI PLUS)检测。并对其进行数据比较和原因分析。结果血浆D-二聚体检测试剂STA-LIATEST D-DI与STA-LIATEST D-DI PLUS数据相比较,[3.63(2.89~10.49)μg/mL vs 0.36(0.26~1.00)μg/mL,P<0.0001],两组数据的差别具有统计学意义。30例患者中21例患者类风湿因子(rheumatoid factor,RF)水平异常,>20 IU/mL(正常参考值上限)。9例患者类风湿因子水平正常,<20 IU/mL。结论血浆D-二聚体检测试剂STA-LIATEST D-DI PLUS对于D-二聚体水平假性增高的标本有很强的的纠正能力。血浆D-二聚体水平>FDP水平时,绝大多数是由于类风湿因子干扰造成的,少部分原因不明确,可能由其他异嗜性抗体导致。