Sensitivity of a New Global Assay for Protein C (PC) Pathway Abnormalities and Potential Significance of an Abnormal Test Result as a Risk Factor/Marker for Thrombosis Independently of Its Sensitivity for PC Pathway Abnormalities.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2635-2635 ◽  
Author(s):  
Pierre A. Toulon ◽  
Nadia Rosencher ◽  
Aurélie Guigon ◽  
Arnaud Simon
Keyword(s):  
Risk Factor ◽  
Predictive Value ◽  
Protein C ◽  
Plasma Samples ◽  
Assay Sensitivity ◽  
Preliminary Results ◽  
Major Orthopedic Surgery ◽  
Abnormal Test Result ◽  
Fv Leiden ◽  
Test Result

Abstract Abnormalities of the protein C (PC) anticoagulant pathway i.e. PC deficiency, PS deficiency and APC-resistant factor Va (FV Leiden) are among the most frequent biological risk factors for venous thromboembolism (VTE) in Caucasian patients but normal results are found in more more than 70% of the cases. This highlights the potential usefulness of a simple assay to screen globally for these abnormalities as this would rationalize the use of expensive individual assays. The HemosIL Thrombopath (Instrumentation Laboratory) is a new chromogenic global assay based on the ability of endogenous APC generated after activation of PC by a snake venom (Protac) to reduce the thrombin generation induced by a reagent containing tissue factor. Optical density is measured after addition of a thrombin-specific chromogenic substrate in the presence (OD A) or absence (OD B) of Protac. It is recommended by the test manufacturer to express results as the Protac-Induced Coagulation Inhibition percentage (PCI%) which corresponds to the ratio [OD B - OD A]/OD B x 100. The assay was performed on the ACL9000 analyzer (IL) using 85% as the cut-off level (PCI%) as we previously determined. Using various lyophilized plasma samples (n=8) both in the normal and abnormal ranges, the within-run precision (evaluated as the CV%, n=17) was found in the range from 1.2% to 2.8% and the between-run precision (CV%, n=48) in the range from 1.6% to 6.3%. The assay sensitivity for PC pathway abnormalities was studied by evaluating a selection of frozen plasma samples from 144 patients with a history of VTE (to be expended). All patients with FV Leiden, PC deficiency (1 with a borderline value), combined defects and lupus anticoagulant (LA) had a decreased response to the assay (PCI% <85%), and the same applied to 28 of the 36 patients with PS deficiency. However, 6 of the 40 patients without any PC pathway abnormality had a decreased response to the assay. So the test sensitivity for PC pathway abnormalities was 91.4% (95%CI=84.2–96), its specificity 85.0% (95%CI=70.2–94.3), its negative predictive value 79.1% (95%CI=63.9–90) and its positive predictive value 94.1% (95%CI=87.5–97.8). Moreover, most (69%) of 13 additional patients carrying the G20210A prothrombin mutation had a decreased test result. PC Def. (n=20) PS Def. (n=36) PC+PS Def. (n=8) FV Leiden (n=27) LA (n=13) No Abnormality (n=40) PCI% (Med/Range) 71.8 (53.8 – 85.3) 74.3 (48.5 – 95.3) 43.5 (19.9 – 70.7) 69.9 (43.8 – 80.9) 69.2 (53.6 – 82.9) 90.5 (73.5 – 98.4) PCI%<85 (n, %) 19/20 (95%) 28/36 (78%) 8/8 (100%) 27/27 (100%) 13/13 (100%) 6/40 (15%) In an attempt to evaluate the clinical relevance of a decreased PCI% in patients without any PC pathway abnormality, the HemosIL Thrombopath assay was performed pre-operatively in patients who underwent major orthopedic surgery. From the preliminary results available, test result was normal in all of the first 34 enrolled patients except in one woman (PCI%=54%) who developped post-operative deep vein thrombosis after total hip replacement and who had no isolated risk factor for thrombosis. This was the only thrombotic episode recorded in the series with a formal 3-month follow-up. These preliminary results suggest that the HemosIL Thrombopath assay is highly sensitive for PC pathway abnormalities and that an abnormal test result could be in itself a risk factor/marker for VTE (p<0.05, Fischer’s exact test).

A New Chromogenic Assay (HemosIL ThromboPath) Is Sensitive to Major Prothrombotic Risk Factors Affecting the Protein C Pathway. Results of a Multicenter Study.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1626-1626
Author(s):  
Pierre A. Toulon ◽  
Mikhail Smirnov ◽  
Mark Triscott ◽  
Armando Tripodi
Keyword(s):  
Risk Factors ◽  
Predictive Value ◽  
Protein C ◽  
Plasma Samples ◽  
Test Results ◽  
Screening Assay ◽  
Specific Test ◽  
Assay Sensitivity ◽  
Chromogenic Assay ◽  
Fv Leiden

Abstract Currently, screening for abnormalities of the protein C (PC) pathway is based on determination of PC, PS and factor V (FV) Leiden-related activated (A) PC resistance. However, more than 70% of the Caucasian patients with thrombophilia yield normal results. This highlights the potential usefulness of a simple global screening assay for these abnormalities rationalizing the use of expensive individual assays. The HemosIL ThromboPath assay (Instrumentation Laboratory) is a new chromogenic assay designed to globally evaluate the functionality of the PC pathway. It is based on the ability of endogenous APC generated after activation of PC by a snake venom extract (Protac) to reduce the thrombin generation induced by a reagent containing tissue factor. Briefly, optical density is measured after addition of a thrombin-specific chromogenic substrate in the presence (OD A) or absence (OD B) of Protac. It is recommended by the test manufacturer to express results as the Protac- Induced Coagulation Inhibition percentage (PiCI%) which corresponds to the ratio [OD B − OD A]/OD B × 100. The within-run and the between run precision is below 6.3% using commercially-available plasma samples both in the normal and pathological ranges. This multicenter trial involving three laboratories was designed in order to determine the ability of this assay to distinguish between subjects with and without PC pathway abnormalities. For that purpose, we retrospectively tested frozen plasma samples obtained from patients with a history of venous thromboembolism and patients family members who were referred to the different participating laboratories in order to screen for biological risk factors for thrombosis, as well as from healthy controls. The ThromboPath assay was locally performed, blinded of the specific test results. In all of three centers, test results were significantly lower (p<0.0001) in subjects who presented with any confirmed PC pathway abnormality than in those without. The cut-off value for the PiCI% which provided the best sensitivity-to-specificity ratio was defined in each participating center as the mean value minus 1 SD using a panel of 30 normal samples. It was found to provide a sensitivity-to-specificity ratio similar to that obtained using ROC-analysis. The assay performed well in carriers of the FV Leiden mutation (n=80), patients with PC deficiency (n=40), combined defects (n=55) and lupus anticoagulant (n=44), with test results below the locally defined cut-off values in 98.8%, 95.0%, 100% and 100% of the subjects, respectively. The assay sensitivity for PS deficiency (n=62) was lower (88.1%). Interestingly, 13.6% of the 272 patients without any PC pathway abnormality had a test result below the locally defined cut-off level. So, using the locally defined cut-off values for the PiCI%, the test sensitivity for all PC pathway abnormalities was 96.1% (95%CI=93.1–98.0), its specificity 86.4% (95%CI=81.8–90.2), its negative predictive value 95.5% (95%CI=92.2–97.7) and its positive predictive value 88.0% (95%CI=83.8–91.4). These results suggest that the HemosIL Thrombopath assay could be useful as part of a prothrombotic screening algorithm. However, further larger-scale prospective studies would be required before drawing definite recommendations concerning the economic impact of the implementation of the HemosIL ThromboPath assay as part of the screening strategy of thrombophilia.

The VITA Project: Heritability of Resistance to Activated Protein C

2000 ◽  
Vol 84 (11) ◽  
pp. 811-814 ◽  
Author(s):  
Alberto Tosetto ◽  
Giancarlo Castaman ◽  
Antonio Cappellari ◽  
Francesco Rodeghiero
Keyword(s):  
Risk Factor ◽  
Protein C ◽  
Genetic Factors ◽  
Activated Protein C ◽  
Population Level ◽  
Phenotypic Resistance ◽  
Apc Resistance ◽  
Parental Response ◽  
High Heritability ◽  
Fv Leiden

SummaryResistance to activated protein C (APC) is a risk factor for venous thromboembolism also in absence of the FV Leiden mutation. To evaluate the influence of genetic factors on APC resistance, we evaluated the heritability of the APC resistance phenotype in 1,519 sib-parent pairs randomly selected from the VITA Project. After adjustment for known influencing factors, a high heritability coefficient (0.58) was observed and parental response to APC was the single most important factor in predicting the corresponding phenotype in sibs. In 32 parentsib pairs in which phenotypic resistance to APC unrelated to FV Leiden was present in both parents and sibs, no additional mutation on the 306-aminoacid residue of FV (FV Cambridge and FV Hong Kong) was found. In these 32 parent-sib pairs, FVIII:C and vWf:Ag levels were not significantly increased and there was no excess prevalence of the R2 allele of exon 13 of FV gene. This study suggests that the response to APC is significantly influenced by genetic factors also at a population level, but the responsible mechanisms are still undefined.

scholarly journals Laboratory Limitations of Excluding Hereditary Protein C Deficiency by Chromogenic Assay: Discrepancies of Phenotype and Genotype

2020 ◽  
Vol 26 ◽  
pp. 107602962091202
Author(s):  
Holger Seidel ◽  
Bianca Haracska ◽  
Jennifer Naumann ◽  
Philipp Westhofen ◽  
Moritz Sebastian Hass ◽  
...  
Keyword(s):  
Predictive Value ◽  
Protein C ◽  
Genetic Defect ◽  
Clotting Time ◽  
Protein C Deficiency ◽  
Assay Sensitivity ◽  
Vte Prophylaxis ◽  
Chromogenic Assay ◽  
Increased Risk ◽  
Proc Gene

Protein C (PC) deficiency is associated with an increased risk for venous thromboembolism (VTE). In daily practice, exclusion of a hereditary PC deficiency is often based on a single determination of PC activity, by either clotting time–based or mostly chromogenic assay. However, diagnosis of hereditary PC deficiency is challenging due to several laboratory and clinical limitations. We compared the potential of PC activity values measured by either chromogenic or clotting time–based assay to predict a variation in the PROC gene. One hundred one (35%) of 287 patients carried variations within the PROC gene, including 2 previously not published variations. In 20 (20%) patients with identified variation, PC activity, determined by chromogenic assay, was within the reference range. For prediction of an underlying genetic defect determined by chromogenic and clotting time–based assay, sensitivity was 80% versus 99%, specificity 75% versus 18%, positive predictive value 64% versus 39%, and negative predictive value (NPV) 88% versus 97%. The lower NPV of chromogenic versus clotting time–based PC assay can be mainly explained by the presence of PC deficiency type IIb. Following our proposed diagnostic algorithm, additional measurement of PC activity by clotting time–based assay in case of a positive VTE history improves detection of this subtype of PC deficiency. Considering potential therapeutic consequences for primary and especially for secondary VTE prophylaxis, genetic analysis is required not only for confirmation but also for clarification of PC deficiency.

scholarly journals Activated protein C resistance as an additional risk factor for thrombosis in protein C-deficient families

Blood ◽  
1994 ◽  
Vol 84 (4) ◽  
pp. 1031-1035 ◽  
Author(s):  
BP Koeleman ◽  
PH Reitsma ◽  
CF Allaart ◽  
RM Bertina
Keyword(s):  
Risk Factor ◽  
Gene Mutation ◽  
Protein C ◽  
Family Members ◽  
Activated Protein C ◽  
Thrombotic Risk ◽  
Increased Risk ◽  
The Family ◽  
Fv Leiden ◽  
Risk For Thrombosis

Abstract Heterozygous protein C deficiency is associated with an increased risk for thrombosis. This association is restricted to a minority of protein C-deficient families, which have been defined as clinically dominant protein C-deficient. In contrast, in the clinically recessive protein C- deficient families, only the homozygous family members are (severely) affected. One possible explanation for this difference in thrombotic risk between families may be the presence of a second hereditary risk factor. A good candidate for this second risk factor is the recently identified resistance to activated protein C (APC). APC resistance, which is associated with a mutation in the FV gene (FV Leiden), is a common and strong risk factor for thrombosis. We show here that the prevalence of the FV Leiden mutation is high among symptomatic protein C-deficient probands (19%). In 6 clinically dominant protein C- deficient families, the segregation of the FV Leiden mutation and the protein C gene mutation was studied. A thrombotic episode had been experienced by 73% of the family members having both the protein C gene mutation and the FV Leiden mutation. In contrast, respectively, 31% and 13% of the family members having either the protein C gene mutation or the FV Leiden mutation had experienced a thrombotic episode. Moreover, the result of a two locus linkage analysis support the assumption that the FV gene and the protein C gene are the two trait loci responsible for the thrombophilia. These results indicate that carriers of both gene defects have an increased risk for thrombosis compared with related carriers of the single defect.

FV HR2 Haplotype as Additional Inherited Risk Factor for Deep Vein Thrombosis in Individuals with a High-Risk Profile

2002 ◽  
Vol 87 (01) ◽  
pp. 32-36 ◽  
Author(s):  
Anna Bossone ◽  
Donatella Coalizzo ◽  
Giovanna D’Andrea ◽  
Vincenzo Brancaccio ◽  
Antonio Ciampa ◽  
...  
Keyword(s):  
Risk Factor ◽  
Deep Vein Thrombosis ◽  
Protein C ◽  
Activated Protein C ◽  
Factor V ◽  
Vein Thrombosis ◽  
Estimated Risk ◽  
Factor V Gene ◽  
Fv Leiden ◽  
Deep Vein

SummaryA number of strongly linked polymorphisms within the Factor V gene (FV HR2 haplotype) has been identified as a cause of resistance to activated protein C, and has suggested a modest risk factor for vein thrombosis. We investigated the frequency of the HR2 haplotype in 433 consecutive patients with confirmed deep vein thrombosis and 326 controls. The HR2 haplotype was more frequent in patients (15.2%) than in controls (10.1%). The risk of thrombosis among carriers of this haplotype was significantly increased (odds ratio: 1.6 [95% CI: 1.0-2.5]). The estimated risk associated with the HR2 haplotype was 1.8 (95% CI: 1.1-2.9) in subjects with (n = 255), and 1.4 (95% CI: 0.8-2.4) in those without (n = 178) acquired risk factors for vein thrombosis. After adjustment for sex, FV Leiden and FII A20210 mutations, the estimated risk of vein thrombosis among carriers of the HR2 haplotype was 1.8 (95% CI: 1.1-2.8). Present data indicate that the HR2 haplotype is independently associated with vein thrombosis among individuals with a highrisk profile.

scholarly journals Activated protein C resistance as an additional risk factor for thrombosis in protein C-deficient families

Blood ◽  
1994 ◽  
Vol 84 (4) ◽  
pp. 1031-1035 ◽  
Author(s):  
BP Koeleman ◽  
PH Reitsma ◽  
CF Allaart ◽  
RM Bertina
Keyword(s):  
Risk Factor ◽  
Gene Mutation ◽  
Protein C ◽  
Family Members ◽  
Activated Protein C ◽  
Thrombotic Risk ◽  
Increased Risk ◽  
The Family ◽  
Fv Leiden ◽  
Risk For Thrombosis

Heterozygous protein C deficiency is associated with an increased risk for thrombosis. This association is restricted to a minority of protein C-deficient families, which have been defined as clinically dominant protein C-deficient. In contrast, in the clinically recessive protein C- deficient families, only the homozygous family members are (severely) affected. One possible explanation for this difference in thrombotic risk between families may be the presence of a second hereditary risk factor. A good candidate for this second risk factor is the recently identified resistance to activated protein C (APC). APC resistance, which is associated with a mutation in the FV gene (FV Leiden), is a common and strong risk factor for thrombosis. We show here that the prevalence of the FV Leiden mutation is high among symptomatic protein C-deficient probands (19%). In 6 clinically dominant protein C- deficient families, the segregation of the FV Leiden mutation and the protein C gene mutation was studied. A thrombotic episode had been experienced by 73% of the family members having both the protein C gene mutation and the FV Leiden mutation. In contrast, respectively, 31% and 13% of the family members having either the protein C gene mutation or the FV Leiden mutation had experienced a thrombotic episode. Moreover, the result of a two locus linkage analysis support the assumption that the FV gene and the protein C gene are the two trait loci responsible for the thrombophilia. These results indicate that carriers of both gene defects have an increased risk for thrombosis compared with related carriers of the single defect.

Factor V Leiden: An Additional Risk Factor for Thrombosis in Protein S Deficient Families?

1995 ◽  
Vol 74 (02) ◽  
pp. 580-583 ◽  
Author(s):  
B P C Koeleman ◽  
D van Rumpt ◽  
K Hamulyák ◽  
P H Reitsma ◽  
R M Bertina
Keyword(s):  
Protein C ◽  
Normal Population ◽  
Factor V Leiden ◽  
Protein S ◽  
Reliable Estimate ◽  
Additional Risk Factor ◽  
Protein S Deficiency ◽  
S Deficiency ◽  
High Prevalence ◽  
Fv Leiden

SummaryWe recently reported a high prevalence of the FV Leiden mutation (R506Q, responsible for Activated Protein C resistance) among symptomatic protein C deficient probands (19%), and the involvement of the FV Leiden mutation in the expression of thrombophilia in six protein C deficient families. Here, we report the results of a similar study in protein S deficient probands and families. Among 16 symptomatic protein S deficient probands the prevalence of the FV Leiden mutation was high (38%). This high prevalence is significantly different from that in the normal population, and is probably caused by the selection of probands for familial thrombosis and protein S deficiency. In 4 families, the segregation of the FV Leiden mutation and the protein S deficiency could be studied. In sibships where both abnormalities were segregating, the percentage of symptomatic individuals with both abnormalities was 80%. Three of the seven subjects with only the FV Leiden mutation, and two out of the three subjects with only protein S deficiency had developed thrombosis. These results indicate that in the families presented here the combination of the FV Leiden mutation and the protein S deficiency is associated with a high risk for thrombosis. A reliable estimate of the penetrance of the single defects is not possible, because the number of individuals with a single defect is too low.

Factor V Leiden Is Associated with Repeated and Recurrent Unexplained Fetal Losses

1997 ◽  
Vol 77 (05) ◽  
pp. 0822-0824 ◽  
Author(s):  
Elvira Grandone ◽  
Maurizio Margaglione ◽  
Donatella Colaizzo ◽  
Marina d'Addedda ◽  
Giuseppe Cappucci ◽  
...  
Keyword(s):  
Protein C ◽  
Strong Association ◽  
Activated Protein C ◽  
Fetal Loss ◽  
Factor V Leiden ◽  
Factor V ◽  
Significant Difference ◽  
History Of ◽  
Fv Leiden ◽  
Caucasian Women

SummaryActivated protein C resistance (APCR) is responsible for most cases of familial thrombosis. The factor V missense mutation Arg506>Gln (FV Leiden) has been recognized as the commonest cause of this condition. Recently, it has been suggested that APCR is associated with second trimester fetal loss. We investigated the distribution of FV Leiden in a sample (n = 43) of Caucasian women with a history of two or more unexplained fetal losses. A group (n = 118) of parous women with uneventful pregnancies from the same ethnical background served as control. We found the mutation in 7 cases (16.28%) and 5 controls (4.24%; p = 0.011). A statistically significant difference between women with only early fetal loss vs those with late events (p = 0.04) was observed. Our data demonstrate a strong association between FV Leiden and fetal loss. Furthermore, they indicate that late events are more common in these patients.

Molecular Characterization of a Type I Quantitative Factor V Deficiency in a Thrombosis Patient that Is “Pseudo Homozygous” for Activated Protein C Resistance

1997 ◽  
Vol 77 (02) ◽  
pp. 252-257 ◽  
Author(s):  
Joan F Guasch ◽  
Ruud P M Lensen ◽  
Rogier M Bertina
Keyword(s):  
Protein C ◽  
Dna Analysis ◽  
Activated Protein C ◽  
Type I ◽  
Factor V ◽  
Sequencing Analysis ◽  
Apc Resistance ◽  
Quantitative Factor ◽  
Factor V Deficiency ◽  
Fv Leiden

SummaryResistance to activated protein C (APC), which is associated with the FV Leiden mutation in the large majority of the cases, is the most common genetic risk factor for thrombosis. Several laboratory tests have been developed to detect the APC-resistance phenotype. The result of the APC-resistance test (APC-sensitivity ratio, APC-SR) usually correlates well with the FV Leiden genotype, but recently some discrepancies have been reported. Some thrombosis patients that are heterozygous for FV Leiden show an APC-SR usually found only in homozygotes for the defect. Some of those patients proved to be compound heterozygotes for the FV Leiden mutation and for a type I quantitative factor V deficiency. We have investigated a thrombosis patient characterized by an APC-SR that would predict homozygosity for FV Leiden. DNA analysis showed that he was heterozygous for the mutation. Sequencing analysis of genomic DNA revealed that the patient also is heterozygous for a G5509→A substitution in exon 16 of the factor V gene. This mutation interferes with the correct splicing of intron 16 and leads to the presence of a null allele, which corresponds to the “non-FV Leiden” allele. The conjunction of these two defects in the patient apparently leads to the same phenotype as observed in homozygotes for the FV Leiden mutation.

Body Mass Index, Follicle-Stimulating Hormone and their Predictive Value in vitro Fertilization

2018 ◽  
Vol 69 (7) ◽  
pp. 1842-1845
Author(s):  
Lavinia Stelea ◽  
Izabella Petre ◽  
Marius Craina ◽  
Brigitha Vlaicu ◽  
Alina Sisu ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Risk Factor ◽  
In Vitro Fertilization ◽  
Body Mass ◽  
Predictive Value ◽  
Follicle Stimulating Hormone ◽  
Vitro Fertilization ◽  
Weight Problems ◽  
Fertility Disorder

The aim of this study was to determine if body mass can be considered a risk factor for infertility, and if we can find any correlations between the age values and the FSH and estradiol values, and between the BMI values and the FSH and estradiol values. Our whole sample contains 100 patients splinted in two groups (pregnant patients N1=57 subjects, 57%, and not � pregnant patients N1=43 subjects,43%). In the first part we conducted our analysis on the whole group and after that we focused the analysis on the two groups and we made some comparisons between the groups. We obtained a medium, extremely significant correlation in all scenarios between the age and the FSH values. This is the best association from all the cases which we tested. In all twelve cases we have a positive correlation (r ] 0). As well, we obtained that a BMI value higher than 25can be considered a risk factor for obtaining a pregnancy (p[0.05, RR ] 1, OR]1) . Our study shows that women who have weight problems have much less chances of conceiving a baby, even if they ovulate normally. The risk of infertility increases proportionally to the extra pounds. Irregular ovulation in women is the most common fertility disorder due to obesity disease.

Sign in / Sign up

Export Citation Format

Share Document