Two SERPINC1 variants affecting N-glycosylation of Asn224 cause severe thrombophilia not detected by functional assays.

Antithrombin deficiency, the most severe congenital thrombophilia, might be underestimated, as some pathogenic variants are not detected by routine functional methods. We have identified 2 new SERPINC1 variants, p.Glu227Lys and p.Asn224His, in 4 unrelated thrombophilic patients with early and recurrent thrombosis that had normal antithrombin activity. In one case, the mutation was identified by whole genome sequencing, while in the 3 remaining cases, the mutation was identified by sequencing SERPINC1 based on a single functional positive finding supporting deficiency. The 2 variants shared a common functional defect, an impaired or null N-glycosylation of Asn224 according to a eukaryotic expression model. Carriers had normal anti-FXa or anti-FIIa activities but impaired anti-FVIIa activity and a detectable loss of inhibitory function when incubating the plasma for 1 hour at 41°C. Moreover, the ß glycoform of the variants, lacking 2 N-glycans, had reduced secretion, increased heparin affinity, no inhibitory activity, and a potential dominant-negative effect. These results explain the increased thrombin generation observed in carriers. Mutation experiments reflected the role that Lysine residues close to the N-glycosylation sequon have in impairing the efficacy of N-glycosylation. Our study shows new elements involved in the regulation of N-glycosylation, a key posttranslational modification that, according to our results, affects folding, secretion, and function, providing new evidence of the pathogenic consequence of an incorrect N-glycosylation of antithrombin. This study supports that antithrombin deficiency is underestimated and encourages the development of new functional and genetic tests to diagnose this severe thrombophilia.

[Factor Xa inhibitors in the prevention and treatment of venous thromboembolism in cancer patients]. / Faktor Xa-hemmere til forebygging og behandling av venøs tromboembolisme ved kreft.

Venous thromboembolism is a common complication of cancer. The prevalence varies according to cancer type and increases proportionally with the stage of cancer. In the past 15-20 years, low molecular weight heparin has been recommended as the first-line treatment. New international guidelines now allow for use of direct factor Xa inhibitors both as prophylaxis and treatment for venous thromboembolism. Prophylaxis should as a general rule only be initiated in patients with moderate to high risk. Bleeding risk assessment is important before starting anticoagulation. Both thrombosis and bleeding risk can change and should therefore be assessed on an ongoing basis. In this clinical review, use of anticoagulation therapy in cancer patients is discussed with particular emphasis on the use of direct factor Xa inhibitors.

The impact of rivaroxaban on primary hemostasis in patients with venous thrombosis.

Factor Xa inhibitors are safe and effective alternatives to warfarin, but several studies indicate that rivaroxaban may cause a different risk profile for bleeding. For instance, while the risk of major bleeding in general may be lower with rivaroxaban than for warfarin, the risk of gastrointestinal bleeding or abnormal uterine bleeding may be higher. The underlying mechanisms for these differences are not known, and the effect of rivaroxaban on primary hemostasis is poorly understood. The aim of this study was to investigate the effect of rivaroxaban on platelet function, P-selectin and von Willebrand factor (VWF) antigen and activity. Patients with venous thrombosis assigned to 3 months of treatment due to temporary risk factors were included. Blood was collected both during (on-treatment) and 4-6 weeks after end of treatment (without treatment). The platelet reactivity was assessed by light transmission aggregometry. P-selectin was measured by an enzyme-linked immunosorbent assay and vWF antigen and activity by latex immunoagglutination assays. Platelet reactivity during on-treatment (trough- and peak concentration) was similar to values without treatment. There was a trend toward a reduction of P-selectin during rivaroxaban treatment (peak concentration) compared to value without treatment (p = 0.06). There were no differences in vWF antigen and activity between the different time-points. We found no difference in platelet reactivity or vWF antigen/activity during rivaroxaban treatment compared with values without treatment. Apart from possibly causing a reduction of P-selectin, rivaroxaban seems not to influence primary hemostasis.

Anxiety, depression and relationship satisfaction in the pregnancy following stillbirth and after the birth of a live-born baby: a prospective study.

BACKGROUND: Experiencing a stillbirth can be a potent stressor for psychological distress in the subsequent pregnancy and possibly after the subsequent birth. The impact on women's relationship with her partner in the subsequent pregnancy and postpartum remains uncertain. The objectives of the study were 1) To investigate the prevalence of anxiety and depression in the pregnancy following stillbirth and assess gestational age at stillbirth and inter-pregnancy interval as individual risk factors. 2) To assess the course of anxiety, depression and satisfaction with partner relationship up to 3 years after the birth of a live-born baby following stillbirth. METHODS: This study is based on data from the Norwegian Mother and Child Cohort Study, a population-based pregnancy cohort. The sample included 901 pregnant women: 174 pregnant after a stillbirth, 362 pregnant after a live birth and 365 previously nulliparous. Anxiety and depression were assessed by short-form subscales of the Hopkins Symptoms Checklist, and relationship satisfaction was assessed by the Relationship Satisfaction Scale. These outcomes were measured in the third trimester of pregnancy and 6, 18 and 36 months postpartum. Logistic regression models were applied to study the impact of previous stillbirth on depression and anxiety in the third trimester of the subsequent pregnancy and to investigate gestational age and inter-pregnancy interval as potential risk factors. RESULTS: Women pregnant after stillbirth had a higher prevalence of anxiety (22.5%) and depression (19.7%) compared with women with a previous live birth (adjusted odds ratio (aOR) 5.47, 95% confidence interval (CI) 2.90-10.32 and aOR 1.91, 95% CI 1.11-3.27) and previously nulliparous women (aOR 4.97, 95% CI 2.68-9.24 and aOR 1.91, 95% CI 1.08-3.36). Gestational age at stillbirth (> 30 weeks) and inter-pregnancy interval <  12 months were not associated with depression and/or anxiety. Anxiety and depression decreased six to 18 months after the birth of a live-born baby, but increased again 36 months postpartum. Relationship satisfaction did not differ between groups. CONCLUSION: Women who have experienced stillbirth face a significantly greater risk of anxiety and depression in the subsequent pregnancy compared with women with a previous live birth and previously nulliparous women.

Classification of stillbirths and risk factors by cause of death--a case-control study.

OBJECTIVE: To investigate risk factors for stillbirths by cause, using the Causes of Death and Associated Conditions (CODAC) classification system for perinatal deaths. DESIGN: Case-control study. SETTING: Two university hospitals in Oslo, Norway, January 1990 through December 2003. SAMPLE: Women with stillbirth after 22 gestational weeks (n = 377) and controls with live births (n = 1 215), and a subsample of 105 cases and 262 controls. METHODS: Socio-demographic, clinical and thrombophilic risk factors for stillbirths were assessed by cause of death in univariate and multivariable logistic regression analyses. Stillbirths were classified according to CODAC based on information from medical records and validated placenta histology. MAIN OUTCOME MEASURES: Causes of stillbirths in percentages, prevalence, odds ratios and adjusted odds ratios for potential risk factors. RESULTS: Approximately half of the women (n = 190) had placental and 19.4% (n = 73) unknown cause of stillbirth. Placental-associated conditions were registered in 18% (n = 68) of cases with a non-placental or an unknown cause. Smoking and small-for-gestational age were more prevalent in all causal groups, compared with controls, whereas twin pregnancy, hypertension and diabetes were more prevalent only among women with placental and unknown causes of stillbirth. The F2rs179963 polymorphism and combined thrombophilia were significant risk factors for stillbirth with placental causes and antiphospholipid antibodies for stillbirth with non-placental causes. CONCLUSIONS: Two-thirds of all stillbirths (68%) were caused by or associated with placental pathology. Risk factors differed somewhat according to cause, apart from smoking and small-for-gestational age, which were significant risk factors across the causal groups.

Arterial events in cancer patients treated with apixaban for venous thrombosis.

INTRODUCTION: In a recent interventional study of cancer patients with newly diagnosed venous thrombosis (VT), we found a high risk of arterial thrombotic events (AT) during treatment with therapeutic doses of apixaban. METHODS: Total 298 cancer patients with VT received apixaban as treatment and secondary prophylaxis for up to 36 months. AT was registered as a serious adverse event, and this is a post hoc analysis of risk factors for AT. Clinical risk factors and concomitant medication were assessed through odds ratios (OR) with 95 % confidence interval using multivariate logistic regression. Biomarkers were assessed by non-parametric testing. RESULTS: AT occurred in 16/298 patients (5.4 %, 95 % confidence interval (CI) 3.1-8.6 %). Median leucocyte count at baseline was higher in patients with AT compared with patients without AT (11 vs. 6.8·109/L, p < 0.01). Clinical factors associated with AT were pancreatic cancer (OR 13.7, 95 % CI 4.3-43.1), ovarian cancer (OR 19.3, 95 % CI 2.3-164.4), BMI <25 percentile (OR 3.1, 95 % CI 1.1-8.8) and previous VT (OR 4.4, 95 % CI 1.4-13.7). Pancreatic cancer had a cumulative incidence of AT of 36 % compared with 0.8 % for all other cancers at 6 months (p < 0.01). Non-steroidal anti-inflammatory drugs (OR 4.9, 95 % CI 1.0-26) and antiplatelet treatment (OR 3.8, 95 % CI 1.2-12.2) were associated with AT. CONCLUSION: In cancer patients with apixaban treated VT, pancreatic cancer was strongly associated with AT. In addition, ovarian cancer, BMI < 25 percentile, previous VT, antiplatelet treatment, non-steroidal anti-inflammatory drug use and high leucocyte count at baseline were associated with AT. The CAP study is registered with the unique identifier NCT02581176 in ClinicalTrials.gov.

High response rate and durable remissions following fludarabine and rituximab combination therapy for chronic cold agglutinin disease.

Most patients diagnosed with primary chronic cold agglutinin disease (CAD) have a clonal lymphoproliferative bone marrow disorder. Treatment with rituximab is the only well-documented effective therapy, leading to 45%-60% partial responses (PR). Complete responses (CR) are rare, and median response duration is only 11 months. In a prospective multicenter trial, 29 patients received rituximab 375 mg/m(2) on days 1, 29, 57 and 85; and fludarabine orally, 40 mg/m(2) on days 1-5, 29-34, 57-61 and 85-89. Twenty-two patients (76%) responded, 6 (21%) achieving CR and 16 (55%) PR. Among 10 patients nonresponsive to rituximab monotherapy, 1 achieved CR and 6 PR. Median increase in hemoglobin level was 3.1 g/dL among the responders and 4.0 g/dL in those who achieved CR. Lower quartile of response duration was not reached after 33 months. Estimated median response duration was more than 66 months. Grade 3-4 hematologic toxicity occurred in 12 patients (41%). In conclusion, fludarabine and rituximab combination therapy is very efficient in patients with CAD. Toxicity may be a concern, and benefits should be carefully weighed against risks in very old and comorbid patients. It remains to be established whether the combination should be first-line or an efficient second-line therapy in CAD patients requiring treatment.

Long-term impact of intrauterine fetal death on quality of life and depression: a case-control study.

BACKGROUND: Intrauterine fetal death (IUFD) is a serious incidence that has been shown to impact mothers' psychological well-being in the short-term. Long-term quality of life (QOL) and depression after IUFD is not known. This study aimed to determine the association between intrauterine fetal death and long-term QOL, well-being, and depression. METHODS: Analyses were performed on collected data among 106 women with a history of intrauterine fetal death (IUFD) and 262 women with live births, 5-18 years after the event. Univariable and multivariable linear and logistic regression models were used to quantify the association between previous fetal death and long-term QOL, well-being and depression. QOL was assessed using the QOL Index (QLI), symptoms of depression using the Center for Epidemiological Studies Depression Scale (CES-D), and subjective well-being using the General Health Questionnaire 20 (GHQ-20). RESULTS: More of the cases had characteristics associated with lower socioeconomic status and did not rate their health as good as did the controls. The QLI health and functioning subscale score was slightly but significantly lower in the cases than in the controls (22.3. vs 23.5, P = .023). The CES-D depressed affect subscale score (2.0 vs 1.0, P = 0.004) and the CES-D global score (7.4 vs 5.0, P = .017) were higher in the cases. Subjective well-being did not differ between groups (20.6 vs 19.4, P = .094). After adjusting for demographic and health-related variables, IUFD was not associated with global QOL (P = .674), subjective well-being (P = .700), or global depression score (adjusted odds ratio = 0.77, 95% confidence interval 0.37-1.57). CONCLUSIONS: Women with previous IUFD, of which the majority have received short-term interventions, share the same level of long-term QOL, well-being and global depression as women with live births only, when adjusted for possible confounders. TRIAL REGISTRATION: The study was registered at http://www.clinicaltrials.gov, with registration number NCT 00856076.

Low dose apixaban as secondary prophylaxis of venous thromboembolism in cancer patients - 30 months follow-up.

BACKGROUND: There are no data on the effect of low-dose anticoagulation as secondary prophylaxis for venous thromboembolism (VTE) in cancer patients. We assessed the efficacy and safety of low-dose apixaban for 30 months, after initial 6 months of full-dose treatment. METHODS: We included 298 patients with cancer and any type of VTE in a single arm interventional clinical trial. All patients were treated with full-dose apixaban (5 mg twice daily) for 6 months. Total 196 patients with active cancer after 6 months treatment continued with apixaban 2.5 mg twice daily for another 30 months. The main endpoints were recurrent VTE, major bleeding and clinically relevant non-major bleeding. RESULTS: During the 30 months of treatment with low-dose apixaban 14 (7.6%; 95% confidence interval (CI) 4.0%-11.7%) patients experienced recurrent VTE, six (3.1%; 95% CI 1.1%-6.5%) experienced major bleeding and 16 (8.1%, 95% CI: 4.7%-12.8%) experienced clinically relevant non-major bleeding. The incidence rate per person month of recurrent VTE was 0.8% (95% CI 0.41-1.6) at 2-6 months with full-dose apixaban, and 1.0% (95% CI 0.5-1.9) at 7-12 months with low-dose apixaban. The incidence rate of major bleeding was 1.1% (95% CI 0.6-2.0) at 2-6 months, and 0.3% (95% CI 0.1-1.0) at 7-12 months. Between 12 and 36 months the incidence rate of recurrent VTE and major bleedings remained low. CONCLUSION: Dose reduction of apixaban to 2.5 mg twice daily seems safe after 6 months of full-dose treatment. After 12 months the incidence rate of recurrent VTE and major bleeding remained low.

Incidence and risk factors of fetal death in Norway: a case-control study.

OBJECTIVE: To estimate incidence and risk factors for intrauterine fetal death (IUFD) in a Norwegian study-population applying two different control groups. DESIGN: Case-control study. SETTING: Two university hospitals in Oslo, Norway, January 1990 through December 2003. SAMPLE: The cases: 377 women with IUFD. CONTROLS: 1) all women delivering at the study-hospitals in the period (facility-based), and 2) 1 215 women with live births at one study-hospital in the period (selected). METHODS: Information from cases and selected controls was collected from medical records. Data on facility-based controls were provided by the Medical Birth Registry of Norway. Data were analyzed using chi-squared test and logistic regression. MAIN OUTCOME MEASURES: Incidence of IUFD and adjusted odds ratios of risk factors. RESULTS: The incidence was 4.1/1 000 deliveries. Small-for-gestational age (SGA) and placental abruption were the strongest risk factors for IUFD. Hypertensive disorders were of low risk if not associated with SGA. Low to moderate risk factors were pre-pregnancy diabetes mellitus, thyroid disease, placenta previa, gestational diabetes, smoking and twin pregnancy. Advanced maternal age was significant when compared with facility-based controls. Risk estimates pointed in the same direction independent of control-group. Hypertension appeared overestimated when using facility-based controls, whereas advanced age was underestimated in the analysis among selected controls. CONCLUSION: SGA has a strong association with IUFD, and the risk of hypertensive disorders is mediated through SGA. The other risk factors, except placental abruption, are of low prevalence and of limited importance in the prevention of a relatively low incidence, although dramatic, event like IUFD.

Treatment of Homozygous Type II Antithrombin Heparin-Binding Site Deficiency in Pregnancy.

Pregnancy is associated with an increased risk of venous thromboembolism (VTE). Previous VTE and severe thrombophilia are important risk factors. Our case was a 36-year-old woman, gravida 6, para 0, with antithrombin (AT) deficiency caused by a homozygous mutation in the heparin-binding site (HBS). Her history included seven prior VTEs, three early and two late pregnancy losses. She was prophylactically treated with both human plasma-derived AT concentrate (hpATC) and low molecular weight heparin (LMWH), resulting in a successful 6th pregnancy and a healthy live born baby. There is limited evidence and guidance on the management of AT deficiency in pregnancy. Dosing and monitoring of anticoagulants, alone or together with hpATC, must be based on individual risk assessment. The severity of clinical manifestations varies with the type of AT deficiency. Characterization of the AT mutation may aid in the decision-making process and optimize pregnancy outcomes.

Thrombosis and bleedings in a cohort of cancer patients treated with apixaban for venous thromboembolism.

INTRODUCTION: The direct oral anti-coagulants (DOAC) edoxaban and rivaroxaban are suggested treatment alternatives for cancer-associated venous thromboembolism (VTE) together with low molecular-weight heparins. New studies indicate that the DOAC apixaban also is an option for cancer-associated VTE. The current study assessed recurrent VTE, arterial thrombosis, bleedings and adverse events in a cohort of apixaban treated cancer patients with VTE. MATERIALS AND METHODS: Single-arm, interventional study of apixaban as treatment of cancer-associated VTE. Inclusion criteria were cancer with objectively verified VTE. Patients received apixaban 10 mg bid for seven days, then 5 mg bid for six months. Primary efficacy and safety outcomes were recurrent VTE and bleeding respectively. This trial is registered with ClinicalTrials.gov identifier NCT02581176. RESULTS: We recruited 298 cancer patients with VTE. During six months treatment, recurrent VTE or death related to VTE occurred in 12 patients (4.0%, 95% confidence interval (CI) 2.1-6.9%). Major bleeding occurred in 16 patients (5.4%, 95% CI 2.8-7.9), most frequently gastrointestinal bleeding. There were no overrepresentation of major bleedings among patients with gastrointestinal cancer (7/126, 5.5%, 95% CI 2.3-11%). Twenty-six patients experienced one or more clinically relevant non-major bleedings (8.9%, 95% CI 5.5-12%). Twelve patients had arterial thrombosis (4.0%, 95% CI 2.1-6.9%), of which the majority were strokes in patients with pancreatic cancer. Death occurred in 35 patients (12%, 95% CI 8.3-16%). CONCLUSION: The frequency of recurrent VTE and major bleedings are in line with other studies on apixaban in cancer-associated VTE. Arterial thrombosis was a frequent serious adverse event.

Elevated Complement C3 and C4 Levels are Associated with Postnatal Pregnancy-Related Venous Thrombosis.

High levels of complement C3 are associated with venous thrombosis (VT) in the general population. We investigated if high C3 and C4 levels were associated with pregnancy-related VT. We undertook the Norwegian VIP study, a case-control study of VT in pregnancy or within 3 months postpartum (cases, n = 313) and women without pregnancy-related VT (controls, n = 353). Determinants of C3 and C4 in the control women were investigated with linear regression and the odds ratio (OR) for pregnancy-related VT was calculated with logistic regression. We found that levels of C3 and C4 were associated with body mass index (BMI), C-reactive protein (CRP); with the coagulation factors (F) fibrinogen, FVIII, and FIX; and with the coagulation inhibitors antithrombin, protein C, protein S, and tissue factor pathway inhibitor. These associations were influenced by CRP levels. The crude OR for pregnancy-related VT was 1.8 (95% confidence interval [CI], 1.1-3.0) for C3 above the 90th percentile and 2.0 (95% CI, 1.2-3.2) for C4 above the 90th percentile. Stratification in antenatal and postnatal VT showed that C3 and C4 were only associated with postnatal VT with an OR for high C3 of 3.0 (95% CI, 1.8-5.0), and for high C4 of 2.6 (95% CI, 1.5-4.6). Adjustment for high FIX and BMI reduced the ORs. We conclude that the association between postnatal VT and C3 and C4 suggests that there is clinically relevant crosstalk between the complement and the coagulation system.

RUNX1-PDCD6 fusion resulting from a novel t(5;21)(p15;q22) chromosome translocation in myelodysplastic syndrome secondary to chronic lymphocytic leukemia.

Leukemic cells often carry chromosome aberrations which generate chimeric genes of pathogenetic, diagnostic, and prognostic importance. New rearrangements giving rise to novel fusion genes define hitherto unrecognized genetic leukemia subgroups. G-banding, fluorescence in situ hybridization (FISH), and molecular genetic analyses were done on bone marrow cells from a patient with chronic lymphocytic leukemia (CLL) and secondary myelodysplasia. The G-banding analysis revealed the karyotype 46,XX,del(21)(q22)[9]/46,XX[2]. FISH on metaphase spreads with a RUNX1 break apart probe demonstrated that part of RUNX1 (from 21q22) had moved to chromosome band 5p15. RNA sequencing showed in-frame fusion of RUNX1 with PDCD6 (from 5p15), something that was verified by RT-PCR together with Sanger sequencing. Further FISH analyses with PDCD6 and RUNX1 home-made break apart/double fusion probes showed a red signal (PDCD6) on chromosome 5, a green signal on chromosome 21 (RUNX1), and two yellow fusion signals, one on der(5) and the other on der(21). Reassessment of the G-banding preparations in light of the FISH and RNA-sequencing data thus yielded the karyotype 46,XX,t(5;21)(p15;q22)[9]/46,XX[2]. The t(5;21)(p15;q22)/RUNX1-PDCD6 was detected only by performing molecular studies of the leukemic cells, but should be sought after also in other leukemic/myelodysplastic cases with del(21q).

Compression Stockings for Preventing the Postthrombotic Syndrome in Patients with Deep Vein Thrombosis.

OBJECTIVE: We conducted a systematic review and meta-analysis to address benefits and harms of using elastic compression stockings after lower-extremity deep vein thrombosis. METHODS: We searched 7 electronic databases through January 15, 2015, including randomized controlled trials (RCTs)/quasi-randomized trials reporting on elastic compression stocking efficacy on postthrombotic syndrome incidence, recurrent venous thromboembolism, mortality, and acute pain after deep vein thrombosis. Two reviewers independently screened records, extracted data, assessed risk of bias, and assessed confidence in effect estimates using Grading of Recommendations Assessment, Development, and Evaluation methodology. We applied random-effects meta-analysis models. RESULTS: We included 5 RCTs (n = 1418) reporting on postthrombotic syndrome. The hazard ratio (HR) for postthrombotic syndrome with elastic compression stockings was 0.69 (95% confidence interval [CI], 0.47-1.02). We have very low confidence in this estimate due to heterogeneity and inclusion of unblinded studies at high risk of bias. Excluding high risk of bias studies, a single large RCT at low risk of bias provided moderate-quality evidence of no effect on postthrombotic syndrome (HR 1.00; 95% CI, 0.81-1.24). Moderate-quality evidence including all 5 studies suggests no effect of elastic compression stockings on recurrent venous thromboembolism (relative risk [RR] 0.88; 95% CI, 0.63-1.24) or mortality (RR 1.00; 95% CI, 0.73-1.37, 5 studies). Moderate-quality evidence from one large RCT does not suggest effect on acute pain after deep vein thrombosis. CONCLUSIONS: The highest-quality evidence available suggests no effect of elastic compression stockings on postthrombotic syndrome or pain relief, from a single large RCT. However, results for preventing postthrombotic syndrome differ substantially across studies, and future guideline updates should reflect uncertainty about treatment effects. Elastic compression stockings are unlikely to prevent death or recurrent venous thromboembolism.

Dilute prothrombin time-based lupus ratio test. Integrated LA testing with recombinant tissue thromboplastin.

The lupus ratio (LR) test is a normalized ratio of the clotting times obtained with low and high phospholipid (PL) concentrations, where the test plasma is mixed 1:1 with normal pooled plasma (NP). As an integrated, automated, and computer-assisted assay, this principle has been applied to the dilute activated partial thromboplastin time (dAPTT) and dilute Russell viper venom time (dRVVT) test systems. In this study, we used recombinant thromboplastin to develop an automated LR test based on the dilute prothrombin time (dPT). Using plasma samples from a selected group of patients (N=92) with a well-defined lupus anticoagulant (LA) status, the dPT-based LR test showed fair agreement with the dAPTT-based LR test (kappa=.60, P<.001) and good agreement with the dRVVT-based LR test (kappa=.78, P<.001) regarding the classification of plasmas as LA-negative or -positive. Most discordant plasmas were low positive. Correlation between dPT- and dRVVT-positive LRs was only moderate (r(s)=.51, P=.002), and correlation between dPT- and dAPTT-positive LRs was nonsignificant (r(s)=.23, P=.18). Using dilutions of pooled LA-positive plasma, the dAPTT-based LR test appeared to be the most sensitive of the three tests. This study confirms the general validity of the LR principle and shows that the dPT-based LR test yields reproducible results. The low coefficients of variation (CV) of the LR assays, combined with a fairly low correlation among the three tests, support the assumption of antibody heterogeneity of LA-positive plasmas and the desirability of performing more than one test.