[Vertebral fractures combined with prolonged activated partial prothrombin time: A case report].

With the development of modern medical standards, autoimmune diseases and their associated successive osteoporosis have received increasing attention in recent years. Patients with autoimmune diseases, due to the characteristics of the disease and the prolonged use of glucocorticoid hormone therapy, may affect the bone formation and bone absorption of the patient, followed by severe successive osteoporosis, thereby increasing the risk of osteoporotic vertebral fractures. Vertebral compression fractures of the spine are common fracture types in patients with osteoporotic fractures. Osteoporosis is a common complication after glucocorticoid therapy in patients with autoimmune diseases. Percutaneous vertebroplasty (PVP) and percutaneous kyphoplasty (PKP) are minimally invasive operation and are commonly used surgical methods for the treatment of osteoporotic vertebral compression fractures. However, due to the operation of spinal puncture during the operation, there are serious surgical risks such as bone cement leakage, spinal epidural hemorrhage, subdural hemorrhage, and subarachnoid hemorrhage in both PVP and PKP. As a result, it is necessary to evaluate the patient' s body before surgery carefully, especially in the case of blood coagulation. This article reports a case of autoimmune disease patient admitted to Peking University People' s Hospital due to lumbar 4 vertebral compression fracture combined with Sjögren' s syndrome. The patient' s preoperative examination showed that the activated partial thromboplastin time (APTT) was significantly prolonged. After completing the APTT extended screening experiment and lupus anticoagulant factor testing, the multi-disciplinary team (MDT) of Peking University People' s Hospital jointly discussed the conclusion that the patient' s test results were caused by an abnormal self-immunity anti-copulant lupus (LAC). Based on the results of the laboratory examination, the patient was considered to be diagnosed with combined antiphospholipid syndrome (APS). For such patients, compared with the patient' s tendency to bleed, we should pay more attention to the risk of high blood clotting in the lower limbs of the patient, pulmonary clots and so on. With timely anti-coagulation treatment, the patient safely passed the peripheral period and was successfully discharged from the hospital. Therefore, for patients with autoimmune diseases with prolonged APTT in the perioperative period, doctors need to carefully identify the actual cause and carry out targeted treatment in order to minimize the risk of surgical and perioperative complications and bring satisfactory treatment results to the patients.

Determination of Thrombogenicity Levels of Various Antiphospholipid Antibodies by a Modified Thrombin Generation Assay in Patients with Suspected Antiphospholipid Syndrome.

Antiphospholipid syndrome (APS) is a hypercoagulable state accompanied by the presence of heterogeneous antiphospholipid antibodies (aPL), which nonspecifically affect hemostasis by the presence of lupus anticoagulans (LA), anticardiolipin antibodies (aCL), antibodies against ß2-glycoprotein-I (anti-ß2GPI), but also non-criteria antibodies such as antibodies against ß2-glycoprotein-I domain I (anti-DI), anti-phosphatidylserine/prothrombin (anti-PS/PT), anti-annexin V, and many others. The main target of the antibodies is the activated protein C (APC) system, the elimination of which can manifest itself as a thrombotic complication. The aim of this study was to determine the thrombogenicity of antibodies using a modified protein C-activated thrombin generation assay (TGA) on a group of 175 samples suspected of APS. TGA was measured with/without APC and the ratio of both measurements was evaluated (as for APC resistance), where a cut-off was calculated ≤4.5 (90th percentile) using 21 patients with heterozygous factor V Leiden mutation (FV Leiden heterozygous). Our study demonstrates the well-known fact that multiple positivity of different aPLs is a more severe risk for thrombosis than single positivity. Of the single antibody positivity, LA antibodies are the most serious (p value < 0.01), followed by aCL and their subgroup anti-DI (p value < 0.05). Non-criteria antibodies anti-annexin V and anti-PT/PS has a similar frequency occurrence of thrombogenicity as LA antibodies but without statistical significance or anti-ß2GPI1 positivity. The modified TGA test can help us identify patients in all groups who are also at risk for recurrent thrombotic and pregnancy complications; thus, long-term prophylactic treatment is appropriate. For this reason, it is proving increasingly beneficial to include the determination antibodies in combination with modified TGA test.

Unexpected, isolated activated partial thromboplastin time prolongation: A practical mini-review.

A common inquiry in coagulation laboratories is how to interpret an unexpected, isolated prolonged activated partial thromboplastin time (APTT). In this context, isolated means together with a normal prothrombin time (PT) and/or normal international normalized ratio (INR). This finding may lead to contact with laboratory doctors for further advice on a diagnostic strategy. Occasionally, the need for a diagnostic algorithm can be subacute, where surgery has to be postponed until an explanation for the isolated, prolonged APTT has been established. Activated partial thromboplastin time as a coagulation test was developed to monitor patients with hemophilia. Different APTT reagents display considerable differences in their sensitivity to deficiencies of coagulation factors. An isolated, prolonged APTT is seen in (a) individuals/patients with lupus anticoagulants, (b) patients in treatment with anticoagulants, mainly heparin, and (c) patients with deficiencies of specific coagulation factors. In this tutorial review, we summarize what may cause an isolated prolonged APTT and we present a simple diagnostic algorithm to differentiate between lupus anticoagulants (common) and factor deficiencies (rare). The identification of an isolated prolonged APTT as well as the underlying cause can be of the utmost importance in ensuring the correct therapeutic follow-up.

Antiphospholipid syndrome - an update.

Antiphospholipid syndrome (APS) is an autoantibody-mediated acquired thrombophilia. It is characterized by the presence of antiphospholipid antibodies (APL) that are directed against phospholipid-binding plasma proteins, such as beta-2-glycoprotein I (b2GPI). Its main manifestations are recurrent vascular thromboses (so-called "thrombotic APS") and pregnancy complications ("obstetric APS"). According to the current consensus criteria, a persistently positive functional lupus anticoagulant (LA) assay and/or the presence of anti-b2GPI and/or anti-cardiolipin antibodies, together with clinical symptoms, is mandatory for the diagnosis of APS. Other clinical features, such as thrombocytopenia, Coombs-positive haemolytic anaemia, heart valve disease, renal microangiopathy and neurologic disorders are also common in APL-positive patients. APS can be associated with other autoimmune disorders, such as systemic lupus erythematosus. In rare cases, catastrophic APS (CAPS) occurs, with the development of excessive thrombosis at multiple sites, usually affecting small vessels and leading to multi-organ dysfunction and organ failure. Treatment usually comprises antithrombotic therapy using antiplatelet and anticoagulant agents. However, there is no consensus concerning the intensity or duration of therapy. Despite apparently adequate anticoagulation, the risk of recurrent thrombosis remains high. For patients with CAPS, a combined therapeutic approach that includes anticoagulation, glucocorticoids, plasma exchange and/or intravenous immunoglobulin seems to be the best treatment option. Keywords: Antiphospholipid syndrome, lupus anticoagulants, anti-cardiolipin, anti-beta-2-glycoprotein I, vascular thrombosis, pregnancy complication.

SAPHO syndrome complicated by multiple venous thrombosis of left lower limb: A case report and literature review.

Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome is an uncommon clinical syndrome with the signs of skin problems and osteoarthropathy as its main features. The pathogenesis of SAPHO syndrome has not been fully elucidated, and multiple complications may be present, including thrombosis. A 39-year-old male patient was diagnosed with SAPHO syndrome, complicated by multiple venous thrombosis of the left lower limb. We conducted a brief review of the current available literature on thrombosis in patients with SAPHO syndrome and speculated that the presence of lower extremity thrombosis in this patient with SAPHO syndrome may be related to physiological structure or antiphospholipid syndrome. Whether positive lupus anticoagulant has an effect on thrombosis in patients with SAPHO syndrome remains to be investigated.

New method to differentiate between lupus anticoagulants, progressive coagulation inhibitors and coagulation factor deficiencies in the mixing tests.

INTRODUCTION: Mixing tests in activated partial thromboplastin time (APTT) are used for the differentiation between lupus anticoagulants (LA), coagulation inhibitors, and factor deficient samples with APTT prolongation. However, the indexes for the differentiation have not been established. The present study aimed to develop new mixing test indexes for the differentiation. METHODS: Twenty-six LA-positive, 8 progressive coagulation factor VIII inhibitor, and 35 coagulation deficient samples were employed. APTT were measured for normal plasma, patient plasma, and mixing plasma prepared at a ratio of 1:1 proportion in both without incubation and 2 h-incubation. New two parameters named as ALD50 and mixture plasma-patient plasma after Warming change rate Subtraction (WaS) calculated from the clotting times of normal, 1:1 mixing and patient samples with/without 2 h-incubation were established. In the samples with WaS result of <10.2%, ALD50 of ≥87.8%, and < 87.8% were defined as LA and coagulation factor deficiency, respectively, and WaS of ≥10.2% defined progressive coagulation factor inhibitors. RESULTS: Sensitivity and specificity to LA were 80.8% and 93.0% for ALD50, and sensitivity and specificity to progressive coagulation factor inhibitor were 100.0% and 100.0% for WaS, respectively. The agreement between sample classification and WaS-ALD50 was 88.4% (61/69). CONCLUSIONS: ALD50 and WaS showed acceptable sensitivity and specificity to LA and progressive coagulation factor inhibitor, respectively. These indexes would be useful for the differentiation between LA, factor deficiency, and progressive coagulation factor inhibitor in the mixing tests.

Antiphospholipid syndrome in children.

Antiphospholipid syndrome (APS) in children is a rare disease associated with significant morbidity and mortality. In comparison with APS in adults, pediatric APS has a more severe presentation with frequent recurrences of thrombotic events and a higher probability of life-threatening catastrophic APS. Nonthrombotic manifestations are also more common in the pediatric age group and can precede thrombosis. New classification criteria have been introduced recently and have not yet been assessed in pediatric patients with APS. In addition to anticoagulation drugs, other novel therapies have emerged including the use of B cell and complement inhibitors, especially in catastrophic APS. The purpose of this review is to provide a broad overview of aPL-related clinical manifestations in pediatric patients based on the analysis of published cohorts and data from the international pediatric APS registry. We also aim to illustrate APS in infants caused by transplacentally transferred maternal aPL, which is very rarely associated with acute thrombotic events in the perinatal period and more frequently with long-term neurodevelopmental abnormalities.

Association of lupus anticoagulants with risk factors for obstetric complications and adverse gestational outcome.

BACKGROUND: Lupus anticoagulant (LA) may be a cause of poor obstetric outcome. OBJECTIVE: To search the association of LA with risk factors for obstetric complications and adverse gestational outcome. METHODS: This retrospective cohort was consisted of 2 groups of pregnancies with poor obstetric history; 1) LA (+) gestations (Study Group, n= 20) and 2) LA (-) gestations (Control Group, 78). All patients were admitted to a special antenatal care program and were examined in terms of risk factors for thrombotic events, placenta-related obstetric complications, and poor gestational outcomes. Patients were administered low-dose low-molecular-weight heparin (LMWH), low-dose salicylic acid and low-dose corticosteroid (if necessary) within the framework of a prophylaxis protocol in addition to their already existing medications. RESULTS: We have shown that adverse gestational outcome was 1.7-fold more frequent in LA (+) pregnancies with poor obstetric history (p= 0.039, 70% vs. 41%). Higher rates of autoimmune diseases and hereditary thrombophilia were observed among LA (+) patients compared to LA (-) gestations (35% vs. 10.3%, p< 0.012 and 55% vs. 19.2%, p< 0.003, respectively). To identify the effectiveness of low-dose LMWH prophylaxis protocol, we compared gestational outcomes and demonstrated that the miscarriage rate was significantly decreased to half in current pregnancies compared to the previous gestations (73.6% vs. 35%, p= 0.003). CONCLUSIONS: Autoimmune diseases and hereditary thrombophilia are more frequent in LA (+) pregnancies, and these women are prone to obstetric problems. Low-dose LMWH and salicylic acid prophylaxis are critical in the management of LA (+) pregnant women.

Interpretation of clot-based lupus anticoagulant assays-Normalizing clotting time against different denominators.

OBJECTIVES: The endpoint for all lupus anticoagulant (LA) assays is a clotting time in seconds. This study aimed to clarify the use of normalizing clotting time to ratio and how the use of different denominators is relevant. METHODS: Whether normalization could reduce reagent variability and possess better diagnostic performances was assessed; denominators included reference interval (RI) mean, local-obtained pooled plasma clotting time, standard plasma clotting time, and control plasma clotting time (CNPPct). Moreover, whether day-to-day variation in CNPPct would impact its application was studied. RESULTS: If not normalized, significant difference existed among different reagent batches; if normalized (against any denominators), no statistically significant difference existed anymore. The validation of in-house RIs achieved a 100% success rate. Normalization against different denominators had different RIs, but the same diagnostic efficacies (when a prolonged LA1 is used to suggest further LA-related testings, normalized LA1 demonstrated a better sensitivity: 1.0 vs. 0.95). Normalization against a "daily" CNPPct (obtained alongside test plasmas day to day) demonstrated low inter-day variations (LA1: ~1%, LA2: ~1%), and it could employ the RI for normalization against a "fixed" CNPPct (obtained alongside normal plasmas when the RI was established). CONCLUSIONS: Normalizing clotting time reduces reagent-batch variability and promotes the adoption of common RIs, and therefore reduces the necessity of establishing RI for new reagent batches. Normalized LA1 is more sensitive when used to suggest further LA-related testings, and therefore reduces the rate of missed LA diagnosis. All denominators are of the same application value. Day-to-day variation in CNPPct did not impact its application as a reliable denominator.

Neutralising rivaroxaban induced interference in laboratory testing for lupus anticoagulant (LA): A comparative study using DOAC Stop and andexanet alfa.

INTRODUCTION: Lupus anticoagulant (LA) investigation in patients on anticoagulant therapy is problematic. Rivaroxaban in particular causes significant interference, prolonging both LA screening and confirmation tests, and falsely raising LA screen/confirm ratios, leading to potential false identification of LA. The Russell Viper Venom Time (RVVT) assay, key to the investigation of LA, is especially sensitive to rivaroxaban. MATERIALS AND METHODS: We assessed cross laboratory (n = 82) testing of four samples to investigate whether rivaroxaban induced interference in LA testing could be neutralised. Testing was performed blind to sample type. The samples comprised: (A) A pool of normal plasma (LA-negative control); (B) sample A spiked with rivaroxaban (200 ng/mL) to create rivaroxaban-induced interference (LA 'false' positive sample); (C) sample B subsequently treated with a commercial 'DOAC-neutraliser' (DOAC Stop); (D) sample B treated with andexanet alfa (200 µg/mL). RESULTS: As expected, the rivaroxaban-spiked sample (B) caused prolongation of most LA-tests, and also generated a falsely prolonged RVVT screen/confirm ratio (median 1.37, compared to 0.97 for sample A). The sample (C) treated with DOAC Stop evidenced a correction in LA-test clotting times, as well as neutralising the false positive LA (median RVVT screen/confirm ratio of 0.99). Although the andexanet alfa treated sample (D) also yielded a low median RVVT screen/confirm ratio of 0.88, it did not fully correct LA-test clotting times. Consistent with test findings, all laboratories interpreted samples A and C as being LA-negative. For sample B (rivaroxaban), 45.3% identified this as LA positive, and 38.7% identified LA interference. Most (61.3%) also identified sample D as LA negative, with the remainder (38.7%) identifying LA interference. CONCLUSIONS: DOAC Stop was able to neutralise the false LA activity induced by rivaroxaban, both in terms of clot-times and LA ratios. In contrast, whilst andexanet alfa negated the rivaroxaban-prolonged LA-ratio, it did not fully correct clot-times, leaving some residual LA interference, and requiring additional testing to investigate prolonged clotting times.

Vertebral fractures combined with prolonged activated partial prothrombin time:A case report / 北京大学学报(医学版)

With the development of modern medical standards,autoimmune diseases and their associ-ated successive osteoporosis have received increasing attention in recent years.Patients with autoimmune diseases,due to the characteristics of the disease and the prolonged use of glucocorticoid hormone thera-py,may affect the bone formation and bone absorption of the patient,followed by severe successive osteo-porosis,thereby increasing the risk of osteoporotic vertebral fractures.Vertebral compression fractures of the spine are common fracture types in patients with osteoporotic fractures.Osteoporosis is a common complication after glucocorticoid therapy in patients with autoimmune diseases.Percutaneous vertebro-plasty(PVP)and percutaneous kyphoplasty(PKP)are minimally invasive operation and are commonly used surgical methods for the treatment of osteoporotic vertebral compression fractures.However,due to the operation of spinal puncture during the operation,there are serious surgical risks such as bone cement leakage,spinal epidural hemorrhage,subdural hemorrhage,and subarachnoid hemorrhage in both PVP and PKP.As a result,it is necessary to evaluate the patient's body before surgery carefully,especially in the case of blood coagulation.This article reports a case of autoimmune disease patient admitted to Peking University People's Hospital due to lumbar 4 vertebral compression fracture combined with Sj?gren's syn-drome.The patient's preoperative examination showed that the activated partial thromboplastin time(APTT)was significantly prolonged.After completing the APTT extended screening experiment and lu-pus anticoagulant factor testing,the multi-disciplinary team(MDT)of Peking University People's Hospi-tal jointly discussed the conclusion that the patient's test results were caused by an abnormal self-immuni-ty anti-copulant lupus(LAC).Based on the results of the laboratory examination,the patient was con-sidered to be diagnosed with combined antiphospholipid syndrome(APS).For such patients,compared with the patient's tendency to bleed,we should pay more attention to the risk of high blood clotting in the lower limbs of the patient,pulmonary clots and so on.With timely anti-coagulation treatment,the patient safely passed the peripheral period and was successfully discharged from the hospital.Therefore,for pa-tients with autoimmune diseases with prolonged APTT in the perioperative period,doctors need to careful-ly identify the actual cause and carry out targeted treatment in order to minimize the risk of surgical and perioperative complications and bring satisfactory treatment results to the patients.

Laboratory testing for lupus anticoagulant (LA) in patients taking direct oral anticoagulants (DOACs): potential for false positives and false negatives.

We and others have previously highlighted the potential problems with testing of lupus anticoagulants (LA) in patients on anticoagulant therapy, including most recently as related to the direct oral anticoagulants (DOACs). Thus, current DOACs in use (e.g., dabigatran, a direct thrombin inhibitor, and apixaban and rivaroxaban, both direct Xa inhibitors), affect a wide variety of coagulation assays, including those used in LA investigation. The Russell viper venom time (RVVT) assay in particular, key to the investigation of LA, is highly sensitive to DOACs. LA is a marker of thrombophilia, and patients who have had a thrombosis may be placed on a DOAC. Thus, there is a high likelihood that LA testing will be requested on patients whilst they are on DOACs. In the current report, we have assessed data from our facility for the past two and a half years for all LA tests performed by RVVT testing, and have evaluated this data with respect to patient anticoagulant status. In total, there were 7170 test requests for RVVT associated testing during the period of data capture. Most LA-RVVT screen results (5008; ∼70%) were within normal limits, thereby excluding LA by RVVT method in most of the patient cohort. All DOACs led to a prolongation in both RVVT screen and confirm assays. However, rivaroxaban affected the screen more than the confirm, leading to higher RVVT ratios, whereas apixaban affected the confirm more than the screen, leading to lower RVVT ratios. LA testing in the presence of DOACs also led to lower intra-patient consistency in LA test results. We conclude that ex-vivo data appears to confirm the potential for false positive (with rivaroxaban) and potential for false negative (with apixaban) identification of LA in patients on DOAC treatment. We also make some recommendations in regards to such testing.

Performance of Activated Partial Thromboplastin Time (APTT): Determining Reagent Sensitivity to Factor Deficiencies, Heparin, and Lupus Anticoagulants.

The activated partial thromboplastin time (APTT) is a useful global assay for the assessment of the contact factor pathway of hemostasis and its inhibitors. The test is usually performed on fully automated analyzers using commercially prepared reagents. The three main clinical areas of interest are detection of factor deficiencies, detection of lupus anticoagulants and in the monitoring of therapy with unfractionated heparin. Methods are described here for assessing APTT reagents for their sensitivity to clotting time prolongation in each of these areas of interest.

Clinical usefulness of the dilute Russell viper venom time test for patients taking warfarin.

Warfarin use often causes false-positive results in the dilute Russell viper venom time test (DRVVT). Thus, three sets of guidelines-those presented by the International Society on Haemostasis and Thrombosis (ISTH), the British Committee for Standards in Haematology (BCSH), and the Clinical and Laboratory Standards Institute (CLSI)-are advocated. We evaluated the clinical usefulness of the testing methods recommended in these three guidelines using laboratory samples. Of the 242 samples from patients using warfarin, 38 were positive for lupus anticoagulant (LA). After adding normal pooled plasma (NPP) as recommended in the ISTH, BCSH, and CLSI guidelines, the number of samples testing positive for LA decreased to 13, 18, and 19, respectively. The number of samples with inconsistent results between the activated partial thromboplastin time and mixing test, and the DRVVT following the ISTH, BCSH, and CLSI guidelines were four of 205 (1.9%), 15 of 242 (6.2%), and 17 of 242 (7.0%), respectively. In patients with an international normalized ratio (INR) ≥3.0, 11 of 37 (29.7%) and 12 of 37 (32.4%) samples showed inconsistent results according to the BCSH and CLSI guidelines, respectively. The accuracy of the DRVVT result may thus decrease in markedly anticoagulated patients.

A combined approach using global coagulation assays quickly differentiates coagulation disorders with prolonged aPTT and low levels of FVIII activity.

Patients with mild/moderate hemophilia (H)A, acquired HA (AHA) and lupus anticoagulants (LA), have prolonged aPTTs with low levels of factor (F)VIII activity, but the differentiation of these disorders is complex and time consuming. We established an approach to quickly differentiate these disorders using comprehensive coagulation tests. Patients' plasmas with mild/moderate HA, AHA, LA without anti-phospholipid syndrome [LA-APS(-)], and LA with APS [LA-APS(+)] were examined using clot waveform analysis (CWA) and thrombin generation test (TGT). Activated protein C (APC) sensitivity was assessed by TGT. CWA revealed similarly prolonged clot times in all groups [NP/mild/moderate HA/AHA/LA-APS(-)/LA-APS(+); 33 ± 1/82 ± 12/116 ± 44/90 ± 29/96 ± 15 s] but significantly different decreased maximal coagulation velocity (3.1 ± 0.1/1.3 ± 0.3/0.9 ± 0.5/1.6 ± 0.3/2.2 ± 0.5). In TGT, AHA group demonstrated severely reduced peak-thrombin levels (362 ± 23/170 ± 27/49 ± 21/158 ± 75/158 ± 99 nM), whilst both LA groups markedly prolonged lag times (4.5 ± 0.3/5.0 ± 0.4/4.7 ± 0.8/12.5 ± 7.7/28.8 ± 11.8 min), suggesting that AHA could be readily identified, but the different LA sub-types failed to be classified. An APC sensitivity demonstrated that 'normalized' APC-induced levels of peak thrombin in LA-APS(+) were significantly lower relative to LA-APS(-) (normalized %inhibition; 5 ± 7/42 ± 39 %). Our studies confirmed that %inhibition by APC was significantly decreased in NP preincubated with purified IgGs from LA-APS(+) compared to LA-APS(-), facilitating differentiation between LA groups. A combined approach using CWA and TGT could be a useful means of differentiating coagulation disorders with prolonged aPTT.

The Development of Marked Collateral Circulation due to Inferior Vena Cava Filter Occlusion in a Patient with Chronic Thromboembolic Pulmonary Hypertension Complicated with Anti-phospholipid Syndrome.

A 30-year-old Japanese man was diagnosed with chronic thromboembolic pulmonary hypertension (CTEPH) with lupus anticoagulants (LAs) in 2003. He underwent pulmonary endarterectomy after the placement of an inferior vena cava filter (IVCF) in 2004, and treatment with warfarin was continued. In 2014, IVCF occlusion and marked collateral circulation were noted during an examination for transient dyspnea; however, his warfarin level was within the therapeutic range for 88.9% of the time from 2003 to 2014. We herein report a rare case of CTEPH and LAs with IVCF occlusion; in such cases, intense treatment may be required.

Development and Implementation of a Coagulation Factor Testing Method Utilizing Autoverification in a High-volume Clinical Reference Laboratory Environment.

BACKGROUND: Testing coagulation factor activities requires that multiple dilutions be assayed and analyzed to produce a single result. The slope of the line created by plotting measured factor concentration against sample dilution is evaluated to discern the presence of inhibitors giving rise to nonparallelism. Moreover, samples producing results on initial dilution falling outside the analytic measurement range of the assay must be tested at additional dilutions to produce reportable results. METHODS: The complexity of this process has motivated a large clinical reference laboratory to develop advanced computer algorithms with automated reflex testing rules to complete coagulation factor analysis. A method was developed for autoverification of coagulation factor activity using expert rules developed with on an off the shelf commercially available data manager system integrated into an automated coagulation platform. RESULTS: Here, we present an approach allowing for the autoverification and reporting of factor activity results with greatly diminished technologist effort. CONCLUSIONS: To the best of our knowledge, this is the first report of its kind providing a detailed procedure for implementation of autoverification expert rules as applied to coagulation factor activity testing. Advantages of this system include ease of training for new operators, minimization of technologist time spent, reduction of staff fatigue, minimization of unnecessary reflex tests, optimization of turnaround time, and assurance of the consistency of the testing and reporting process.

Screening for lupus anticoagulants in patients treated with vitamin K antagonists.

INTRODUCTION: The dRVVT test for detecting lupus anticoagulants (LA) is difficult to interpret when patients are treated with vitamin K antagonists (VKA). METHODS: We performed LA testing in 33 VKA-treated patients with definite antiphospholipid syndrome (APS) and compared the results with 100 controls subjects not receiving VKA and 110 APL-negative patients anticoagulated for reasons other than APS. RESULTS: Compared with the dRVVT ratio before the initiation of VKA therapy, a higher cutoff value, defined as the 99th percentile, was established for VKA-treated patients with INR values between 2.0 and 3.5. A dRVVT ratio of >1.7 yielded a sensitivity of 81.3%, specificity of 99.1%, and positive and negative predictive values of 98.7% and 85.8%, respectively, for detecting LA. Cohen's kappa coefficient indicated good agreement for the dRVVT ratio obtained from testing with and without VKA treatment (κ = 0.813; 95% CI: 0.773-0.853), which was higher (κ = 0.941; 95% CI: 0.917-0.965) when the LA diagnosis was based on the results of both the dRVVT and a second test system (i.e., Mixcon-LA assay). CONCLUSIONS: Lupus anticoagulants testing in VKA-treated patients with APS according to current guidelines appears to be possible for the majority of patients without discontinuing anticoagulant therapy.

Commonalities and contrasts in recent guidelines for lupus anticoagulant detection.

Updates to guidelines covering lupus anticoagulant (LA) detection have recently been published by the International Society on Haemostasis and Thrombosis (ISTH) and British Committee for Standards in Haematology (BCSH), in 2009 and 2012, respectively. The Clinical and Laboratory Standards Institute (CLSI) published its first LA guideline in 2014. Cross-panel agreement exists on sample manipulation, use of dRVVT analysis, conversion of clotting times to ratios, calculations to demonstrate phospholipid dependence, mixing test interpretation and provision of interpretive reporting. Whilst ISTH restricts assay choice to just dRVVT and activated partial thromboplastin time, BCSH and CLSI consider the case for additional tests. All panels acknowledge the potential for false-negative mixing tests, yet they remain mandated by ISTH and BCSH, the latter, however, indicating that a negative mixing test need not exclude a LA if testing on undiluted plasma is unequivocal. CLSI reprioritizes test order to screen-confirm-mix to reduce false-negative reporting when antibodies are diluted to undetectable levels in mixing tests. Recommendations differ on how to derive cut-off levels, particularly in view of the realities of relatively low donor numbers. Each guideline considers testing of anticoagulated patients, BCSH and CLSI endorsing Taipan snake venom time as a useful supplementary assay in patients on vitamin K antagonists. Although full consensus is not apparent, these publications represent significant moves towards engendering common practices.