Challenges in implementation of ISTH diagnostic algorithm for diagnosis and classification of factor XIII deficiency in Iran

Automation of a Factor XIII Activity Assay Utilizing a Plasma Blank Measurement

Factor XIII (FXIII) is an essential coagulation factor that stabilizes fibrin clots and allows the clot to resist fibrinolysis. Inherited or acquired FXIII deficiency is a severe bleeding disorder with manifestations that can include fatal intracranial hemorrhage. Accurate FXIII laboratory testing is necessary for diagnosis, subtyping, and treatment monitoring. The recommended first-line test is FXIII activity, most commonly performed by commercial ammonia release assays. In these assays, it is important to perform a plasma blank measurement to correct for FXIII-independent ammonia production, which can lead to clinically significant overestimation of FXIII activity. Automated performance of a commercial FXIII activity assay (Technoclone, Vienna, Austria), including blank correction, on the BCS XP instrument is described.

Noninvasive prenatal diagnosis of congenital factor XIII deficiency in Iran

Congenital factor (F) XIII deficiency is a rare coagulation factor deficiency that is inherited in an autosomal recessive manner. FXIII deficiency presents various clinical manifestations, such as intracranial hemorrhage (ICH), which is the most common cause of morbidity and mortality. As ICH can occur in the neonatal period, prenatal diagnosis (PND) is an effective way to reduce neonatal ICH and its associated fatal consequences. In this study, we investigated a noninvasive prenatal diagnosis (NIPD) method, cell-free fetal DNA (cffDNA), for PND in FXIII deficiency. This study was conducted on seven pregnant women in the first trimester. After extraction of cffDNA from maternal plasma, PCR-restriction fragment length polymorphism (PCR-RFLP) was performed to find the underlying F13A gene mutations previously identified in the family members. PCR-RFLP was also performed on postnatal DNA samples. Sanger sequencing was performed to confirm the results. Four cases were heterozygous for F13A gene mutations, whereas three were unaffected. PCR-RFLP results for cffDNA and postnatal DNA samples were identical, and Sanger sequencing confirmed the results. cffDNA is a noninvasive and effective method for PND in congenital FXIII deficiency.

Management of Neuraxial Analgesia in a Parturient with Factor XIII Deficiency: A Case Report and Proposed Management Algorithm

Factor XIII (FXIII) deficiency is a rare coagulation defect that can be associated with significant bleeding. A 28-year-old pregnant woman, with a history of hemorrhagic stroke secondary to severe congenital FXIII deficiency, presented in active labor requesting an epidural. Factor XIII levels had been monitored throughout her pregnancy and treated with intermittent factor XIII infusions to maintain factor levels above 30% of normal. After careful multidisciplinary peripartum evaluation and FXIII replacement, neuraxial analgesia was performed without complication. Neuraxial analgesia can be performed without complication in patients with FXIII deficiency if FXIII levels are carefully managed and no other coagulopathy exists.

How to Assess Founder Effect in Patients with Congenital Factor XIII Deficiency

Congenital factor XIII (FXIII) deficiency is an extremely rare bleeding disorder (RBD) with estimated prevalence of one per 2 million in the general population. The disorder causes different clinical manifestations such as intracranial hemorrhage (ICH), recurrent miscarriage, umbilical cord bleeding, etc. High incidence of the disorder might be due to founder effect. To assess founder effect, haplotype analysis is an important step. For this purpose, suitable and reliable genetic markers such as microsatellites (Hum FXIIIA01 and HumFXIIIA02) and single nucleotide polymorphisms (SNP) are suggested. In the present study we tried to describe evaluation of founder effect in patients with congenital FXIII deficiency via haplotype analysis using suitable genetic markers.

Laboratory Assessment of Coagulation Factor XIII

Laboratory diagnosis of congenital and acquired deficiencies of coagulation factor XIII (FXIII) can be challenging. Determination of FXIII function requires specific and sensitive assays which are not always available. This brief review article summarizes currently used FXIII assay methods, their principles and difficulties, and discusses the recommended diagnostic workup in case of a suspected FXIII deficiency. The article also briefly touches on experimental methods used in FXIII research.

Detection of Factor XIII deficiency: data from multicentre exercises amongst UK NEQAS and PRO-RBDD project laboratories

INTRODUCTION

FXIII deficiency is a rare bleeding disorders, and specific FXIII assays are recommended to detect this deficiency. We investigated the performance and accuracy of FXIII investigations in two exercises, comparing centres enrolled in the PRO-RBDD project (prospective data collection on patients with fibrinogen and Factor XIII deficiencies), and UK NEQAS BC centres.

METHODS

Samples from a FXIII deficient subject and a normal donor were sent to participating centres, to investigate for FXIII deficiency, and interpret their results. Median, coefficient of variation and range were determined.

RESULTS

Results were returned from 98 UK NEQAS BC and 28 PRO-RBDD centres. Up to 40% of UK NEQAS BC and 52% of PRO-RBDD centres reported clot solubility results - with diagnostic errors by two NEQAS BC centres (false negatives for the FXIII deficient sample) and one PRO-RBDD centre (false positive for the normal sample). Over 70% of UK NEQAS BC centres and PRO-RBDD centres performed FXIII assays. Median results were similar between the two groups, with the exception of sample 3 in survey 2 (5.5 vs. 14.0 μ/dl for UK NEQAS BC and PRO-RBDD centres respectively, P < 0.001). Diagnostic errors were made by 2 UK NEQAS BC centres.

CONCLUSION

Approximately 70% of centres now employ FXIII assays, complying with international recommendations. However, solubility tests continue to be used. Our data show this can be successful, depending on the sensitivity of the method in use. Diagnostic errors are made by centres using both solubility screens and FXIII assays, and laboratories should ensure good quality assurance procedures to improve diagnostic accuracy.

Agreement between factor XIII activity and antigen assays in measurement of factor XIII: A French multicenter study of 147 human plasma samples

INTRODUCTION

Factor XIII (FXIII) deficiency is a rare hemorrhagic disorder whose early diagnosis is crucial for appropriate treatment and prophylactic supplementation in cases of severe deficiency. International guidelines recommend a quantitative FXIII activity assay as first-line screening test. FXIII antigen measurement may be performed to establish the subtype of FXIII deficiency (FXIIID) when activity is decreased.

METHODS

The aim of this multicenter study was to evaluate the analytical and diagnostic levels of performance of a new latex immunoassay, K-Assay^® FXIII reagent from Stago, for first-line measurement of FXIII antigen. Results were compared to those obtained with the Berichrom^® FXIII chromogenic assay for measurement of FXIII activity. Of the 147 patient plasma samples, 138 were selected for analysis.

RESULTS

The accuracy was very good, with intercenter reproducibility close to 7%. Five groups were defined on FXIII activity level (<5% (n = 5), 5%-30% (n = 23), 30%-60% (n = 17), 60%-120% (n = 69), above 120% (n = 24)), without statistical differences between activity and antigen levels (P value >0.05). Correlation of the K-Assay^® with the Berichrom^® FXIII activity results was excellent (r = 0.919). Good agreement was established by the Bland and Altman method, with a bias of +9.4% on all samples, and of -1.4% for FXIII levels lower than 30%. One patient with afibrinogenemia showed low levels of Berichrom^® FXIII activity but normal antigen level and clot solubility as expected.

CONCLUSIONS

The measurement of FXIII antigen using the K-Assay^® is a reliable first-line tool for detection of FXIII deficiency when an activity assay is not available.

Guidelines for laboratory diagnosis of factor XIII deficiency

Factor XIII (FXIII) deficiency is an extremely rare hemorrhagic disorder with an approximate worldwide incidence of one per two million. With current tests, diagnosis of this disease can be made more precisely. However, factors such as the number of patients with FXIII deficiency (FXIIID), available diagnostic coagulation tests and the number of molecular studies have affected the diagnosis of FXIIID in different parts of the world. Various laboratory approaches can be used, including screening and diagnosis of the disorder in countries with a relatively high rate of FXIIID and recurrent mutation(s) with a simple polymerase chain reaction-restriction fragment length polymorphism analysis or polymerase chain reaction-sequencing for detection of one or a few specific mutations. In other countries, two different laboratory approaches can be used, depending on available coagulation tests. In less-equipped coagulation laboratories, the clot solubility test remains the only diagnostic test for FXIIID. Even in these countries, at least one referral laboratory should perform FXIII activity and, if possible, confirmation of FXIIID by molecular analysis. In countries with well equipped coagulation laboratories, FXIII activity should be used to screen suspected FXIIID patients; more specific tests such as molecular analysis should be used for confirmation. This study suggests a simple, reliable and flexible algorithm for early diagnosis of FXIIID, and may, with one-time diagnosis of FXIIID, reduce the rate of morbidity and mortality in patients with the disorder.

Effects of Factor XIII Deficiency on Thromboelastography. Thromboelastography with Calcium and Streptokinase Addition is more Sensitive than Solubility Tests

Background

Homozygous or double heterozygous factor XIII (FXIII) deficiency is characterized by soft tissue hematomas, intracranial and delayed spontaneous bleeding. Alterations of thromboelastography (TEG) parameters in these patients have been reported. The aim of the study was to show results of TEG, TEG Lysis (Lys 60) induced by subthreshold concentrations of streptokinase (SK), and to compare them to the clot solubility studies results in samples of a 1-year-old girl with homozygous or double heterozygous FXIII deficiency.

Case

A year one girl with a history of bleeding from the umbilical cord. During her first year of life, several hematomas appeared in soft upper limb tissue after punctures for vaccination and a gluteal hematoma. One additional sample of a heterozygous patient and three samples of acquired FXIII deficiency were also evaluated.

Materials and Methods

Clotting tests, von Willebrand factor (vWF) antigen and activity, plasma FXIII-A subunit (pFXIII-A) were measured by an immunoturbidimetric assay in a photo-optical coagulometer. Solubility tests were performed with Ca²⁺-5 M urea and thrombin-2% acetic acid. Basal and post-FXIII concentrate infusion samples were studied. TEG was performed with CaCl₂ or CaCl₂ + SK (3.2 U/mL) in a Thromboelastograph.

Results

Prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time, fibrinogen, factor VIIIc, vWF, and platelet aggregation were normal. Antigenic pFXIII-A subunit was < 2%. TEG, evaluated at diagnosis and post FXIII concentrate infusion (pFXIII-A= 37%), presented a normal reaction time (R), 8 min, prolonged k (14 and 11min respectively), a low Maximum-Amplitude (MA) ( 39 and 52 mm respectively), and Clot Lysis (Lys60) slightly increased (23 and 30% respectively). In the sample at diagnosis, clot solubility was abnormal, 50 and 45 min with Ca-Urea and thrombin-acetic acid, respectively, but normal (>16 hours) 1-day post-FXIII infusion. Analysis of FXIII deficient and normal plasma mixtures (< 2–102% of pFXIII-A), showed that Ca-urea solubility was abnormal at pFXIII-A < 9%, thrombin-acetic acid at pFXIII-A<18%, but TEG MA and elasticity at 23% and Lys60 with SK at pFXIII-A< 40%.

Conclusions

TEG parameters MA and elasticity, and Lys 60 in TEG either with Ca²⁺ or Ca²⁺ and SK are more sensitive to low levels of pFXIII than solubility tests. The increased Lys60 induced by a subthreshold concentration of SK could probably reflect the clot characteristics “in vivo” in many patients with pFXIII levels between 5–40% and could be potentially considered as screening test.

Laboratory Diagnosis of Factor XIII Deficiency in Developing Countries: An Iranian Experience

Factor XIII (FXIII) deficiency is an extremely rare bleeding disorder with an approximately 12-times higher than the rest of the world. The International Society for Thrombosis and Hemostasis (ISTH) suggested a standard algorithm for precise diagnosis and classification of FXIII deficiency (FXIIID). However, due to lack of investment in proper equipment and procedures in Iran, almost no part of this algorithm can be used to diagnose Iranian patients. Thus, this study proposes a guideline for accurate molecular and laboratory diagnosis of FXIIID based on the available tools. Because this study suggests a simple and reliable algorithm for early diagnosis, it can therefore, reduce the rates of morbidity and mortality of FXIIID patients with this condition.

Blood coagulation factor XIII and factor XIII deficiency

Factor XIII (FXIII) is a multifunctional pro-γ-transglutaminase that, in addition to its well-known role in hemostasis, has a crucial role in angiogenesis, maintenance of pregnancy, wound healing, bone metabolism, and even cardio protection. FXIII deficiency (FXIIID) is a rare bleeding disorder (RBD) with an estimated incidence of one per two million that is accompanied by life-threatening bleeding such as umbilical cord bleeding, recurrent spontaneous miscarriage, and intracranial hemorrhage (ICH). Today, the disease is successfully managed by FXIII concentrate and recombinant FXIII for prophylaxis, management of minor and major bleeding, treatment of ICH, and successful delivery in women with recurrent pregnancy loss. Molecular analysis of patients with FXIIID revealed a wide spectrum of mutations, most frequently missense mutations in the FXIII-A subunit, with a few recurrent mutations observed worldwide. In vitro expression studies revealed that most of the missense mutations cause intracellular instability of the FXIII protein and, subsequently, FXIIID.