Comparison of four D-dimer assays in the context of venous thromboembolism in the emergency department.

INTRODUCTION: This observational study conducted across seven emergency care units compares the efficacy of four D-dimer detection methods, namely HemosIL D-dimer HS (HS), HemosIL D-dimer HS-500 (HS-500), VIDAS D-dimer (VIDAS), and HemosIL AcuStar D-dimer (ACUSTAR). The primary focus is on patients with a clinical suspicion of deep venous thrombosis (DVT) or pulmonary embolism (PE). METHODS: A total of 149 samples were collected from patients with suspected DVT or PE. The confirmation of DVT/PE was based on calf ultrasound or computed tomography-Angiography. Direct comparisons were made between the different detection methods, considering both their analytical performance and clinical utility. Additionally, the impact of an age-adjusted cut-off on the diagnostic accuracy of each method was assessed. RESULTS: The results revealed comparable negative predictive value, sensitivity, and specificity across the methods, with a notable exception of increased specificity for HS compared with HS-500 (50.8% vs. 41.5%, p = 0.03). Further analysis incorporating an age-adjusted cut-off demonstrated a significant improvement in specificity for HS. When using the age-adjusted cut-off, HS exhibited a substantial increase in specificity compared with HS-500 (63.1% vs. 49.2%, p = 0.004) and demonstrated significantly higher specificity compared with VIDAS (63.1% vs. 53.8%, p = 0.04). CONCLUSION: The study emphasizes the nonuniversal effect of an age-adjusted cut-off and discusses the potential necessity for different cut-off values, particularly in the case of HS-500. These findings contribute to the understanding of D-dimer detection methods in the context of DVT and PE, providing insights into their relative performances and the potential optimization through age-adjusted cut-offs.

Lupus anticoagulant: a multicenter study for a standardized and harmonized reporting.

Laboratory assessment of Lupus anticoagulant (LAC) is very challenging because of inter and intralaboratory variability, which makes it difficult to standardize and harmonize results expression. Five hospital laboratories in North-eastern Italy shared their efforts and their experience in a cross-laboratory study, conducting the diagnostic process as homogeneously as possible and providing a better interpretation for LAC positivity. Hundred normal samples from healthy subjects (20 from each center) were processed to confirm negative upper limits and calculate positivity cutoffs of LAC integrated assays, that is dilute Russell's viper venom time (dRVVT) and silica clotting time (SCT). Moreover, 311 samples previously diagnosed by the laboratories as positive for LAC were analyzed to characterize different positivity levels for each assay. As far as the analysis of healthy subjects is concerned, negative upper limits are set at 1.17 and 1.19 for dRVVT and SCT screen ratio, respectively. Positivity cutoffs are set at 1.20 for dRVVT and 1.23 for SCT, expressed as Test Ratio calculated on screen and confirm integrated tests. Positive results for each integrated assay are subsequently divided into three subgroups: weak, moderate and strong; the results obtained are presented as a score proposal that can provide LAC interpretation. The combined use of both dRVVT and SCT assays and the definition of different positivity levels may lead to clearer, more objective LAC reporting. An interpretative table for LAC-proposed score provides LAC-positive results and it is now adopted by all centers involved in the study.

A family with factor-XI deficiency due to a compound heterozygosis between Gln 47 Pro (new mutation) in exon 3 and Leu 619 Pro in exon 15.

A new factor XI mutation (Gln 47 Pro) has been found in combination with another known mutation (Leu 619 Pro) in a female patient with FXI deficiency and a moderate bleeding tendency. FXI activity and antigen in the proposita were 2% activity and less than 5% of normal, respectively. The parents are not consanguineous and are asymptomatic. The father is heterozygote for the new mutation whereas the mother is heterozygote for the known mutation. Other family members are heterozygotes for either one of the two mutations. The new mutation is not a polymorphism as it was not found in the population of the area. The geographical area, north-east of Italy, of the present family is the same area where a cluster of another new mutation (Ile 436 Lys) was recently reported. No relation was found between the present family and those with the previous mutation.

Cooperation experience in a multicentre study to define the upper limits in a normal population for the diagnostic assessment of the functional lupus anticoagulant assays.

BACKGROUND: Phospholipid-dependent coagulation tests for lupus anticoagulant (LA) are considered an important step for the diagnosis of anti-phospholipid syndrome; however, LA laboratory detection is difficult because of many variables. Five hospital laboratories, located in a North-Italy area and using the same method for LA testing, cooperated to standardise sample treatment and analytical procedure in order to define the upper values for LA negativity. METHODS: In total, 200 normal subjects (40 for each centre) were studied for six LA functional assays, using the same procedure, reagent lot and analyser type. The first tests done were LA screen and LA confirm assays, based on diluted Russell's Viper Venom Time, with low and high phospholipid content, respectively. The second tests performed were silica clotting time screen and confirm assays, based on activated partial thromboplastin time, with low and high phospholipid content, respectively. Finally, two mixing assays were executed for both screening assays, diluting patient sample with a pool prepared with plasma collected from the study population. RESULTS: Data analysis demonstrated a difference between centres for all assays when results were expressed in seconds; the difference disappeared when results are normalised with the local mean normal value of each centre and are expressed as a normalised ratio. The study population was normally distributed; so the value corresponding to 99th percentile was used as limit value for LA negativity. Values expressed as normalised ratio, for LA and silica clotting time screenings were 1.22 and 1.23, respectively. CONCLUSIONS: The study allowed us to define a uniform approach to LA testing and evaluation for laboratories employing the same methods.

A cluster of factor XI-deficient patients due to a new mutation (Ile 436 Lys) in northeastern Italy.

A new mutation (Ile 436 Lys) was found in a cluster of patients in northeastern Italy. The mutation was present in five patients at the homozygote level and in one patient as a compound heterozygote with an already known mutation namely Glu 117 stop. All these patients showed a mild bleeding tendency mainly associated with deliveries or surgery. The first two patients were two sisters, and their parents were consanguineous. The third patient was the only homozygote in the family, and parents apparently were not consanguineous. The fourth and fifth patients were a brother and a sister, and in this case too, parents were not consanguineous. The sixth patient, a compound heterozygote, negated also the existence of consanguinity between his parents. There were also seven heterozygotes among the family members of the patients homozygous for this new mutation (Ile 436 Lys). Finally, there were two heterozygotes for the Glu 117 stop mutation in the family of the sixth patient. The heterozygotes, regardless of the mutation, were asymptomatic. The Ile436Lys mutation is characterized by low factor XI activity and antigen, namely is a cross-reaction material negative form. Molecular modeling indicates that the Ile436Lys mutation causes a large conformational change within the 432-442 loop. No relation could be traced among the different families; however, all their ancestors were autochthonous of the same two small towns. Furthermore, no Jewish ancestry could be found. The close geographical area in which all these patients were found and the absence of the same mutation in the general population of the area strongly suggests a founder effect and that the mutation is responsible for the defect. The compound heterozygosis with the Glu 117 stop mutation, common among Jews, was not surprising because of the past strict ties of the Republic of Venice with the Middle East.

Genetic study in patients with factor XII deficiency: a report of three new mutations exon 13 (Q501STOP), exon 14 (P547L) and -13C>T promoter region in three compound heterozygotes.

A group of 29 patients with congenital factor XII (FXII) deficiency belonging to nine distinct families have been investigated. All were cases of true deficiency in the sense that there was no discrepancy between FXII activity and FXII antigen. From a clotting point of view, 11 patients appeared homozygous, as both FXII activity and antigen were very low (< or =1% and traces of antigen). In other words, they were cases with no cross-reactivity material. In the heterozygotes, FXII activity and antigen were about 50% of normal in all cases. The molecular studies revealed that seven patients were real homozygotes for the mutation -8G>C in the promoter region confirming the conclusions reported by coagulation tests. On the contrary, the remaining patients with a homozygote-like phenotype were instead found to be compound heterozygous for two distinct mutations. Three of these mutations were new mutations, namely the combination of -8G to C with 501Q to T (exon 13), 547P to L (exon 14) and -13C to T in the promoter, respectively. The remaining mutations seen were not new. It is interesting that all compound heterozygotes showed a clotting and immunological pattern similar to that shown by homozygotes, namely very low FXII activity and antigen. The new mutations were not present in the group of 98 normal persons of both sexes with the same geographical background. The wide diffusion of the -8G>C mutation in this group of patients coming from a limited geographical area suggests a founder effect. The significance and importance of genetic analysis in addition to clotting and immunological studies in FXII deficiency is emphasized.

Plasmapheresis therapy in pemphigus vulgaris and bullous pemphigoid.

Blistering dermatitises are characterized by the presence of blisters that begin owing to acantholysis (intraepidermic blister) such as pemphigus vulgaris (PV) or owing to dermoepidermic detachment (subepidermic blister) such as bullous pemphigoid (BP). Both diseases are autoimmune pathologies characterized by the presence of autoantibodies against specific adhesion molecules of the skin and mucous membranes. PV, in which oral lesions are always present, has a progressive course that, if the disease is not treated, nearly always brings to death from sepsis within a few years. In BP, oral lesions are rare and the disease, that is most frequent in older individuals, has a chronic course with spontaneous remissions. Systemic corticosteroids and immunosuppressants are the mainstay of treatment of these two diseases. Although this therapy had reduced the mortality of the two pathologies it is associated with serious side effects. To reduce the corticosteroids dose and to improve the symptomatology in resistant therapy cases, we treated five patients with several procedures of plasma exchange. Four patients were affected by BP and one by PV. Their disease severity at onset of plasmapheresis ranged from mild to severe. One of 5 patients suffered a plasmapheresis side effect. All patients responded with complete remission of symptomatology and had a prednisone dosage reduction until 70%. Plasmapheresis is an effective treatment for PV and BP patients who have been unresponsive to conventional therapy, for those for whom conventional drugs are contraindicated, for those who show severe clinical manifestations and for those who need high doses of corticosteroids and immunosuppressants to keep the disease under control.