Laboratory Assessment of Coagulation Factor XIII

Correlation of factor XIII subunit A with factor XIII activity in a population of parturient women

BACKGROUND

The role of factor XIII in acute bleeding situations is gaining more and more importance. It has previously been shown that prepartum factor XIII activity has a significant impact on postpartum blood loss. Whether factor XIII antigen behaves in a similar manner is unknown. As postpartum hemorrhage is one of the leading causes of maternal morbidity and mortality worldwide and factor XIII antigen determination might be available more readily in some centers as compared to factor XIII activity, this is an important question to answer, especially in the emergency situation of a postpartum hemorrhage.

OBJECTIVE

To assess the correlation of prepartum factor XIII antigen with prepartum factor XIII activity and to evaluate the correlation between prepartum factor XIII antigen on measured postpartum blood loss.

METHODS

This is a secondary analysis of a prospective cohort study which analyzed the impact of prepartum blood coagulation factor XIII activity on postpartum blood loss in 1300 women at the University Hospital Zurich, Switzerland between October 2015 and November 2016 ("PPH-1300 study"). Blood loss was quantified using a previously validated technique. The association of factor XIII activity and factor XIII antigen was assessed by means of a Spearman rank correlation and differences were displayed using Bland-Altman plot and Passing-Bablok regression. The effect of the prepartum factor XIII antigen on blood loss was estimated by continuous outcome logistic regression.

RESULTS

Prepartum factor XIII activity significantly correlated with prepartum factor XIII antigen (Spearman rank correlation coefficient for prepartum values 0.89, p < 0.001 and postpartum values 0.902, p < 0.001). Elevated values of prepartum factor XIII antigen showed a trend toward lower measured postpartum blood loss.

CONCLUSION

The correlation of factor XIII activity with factor XIII antigen (subunit A) in a large real-world sample as well as an association of prepartum factor XIII antigen and postpartum blood loss is observed. Factor XIII antigen determination, a highly automatable test, could be useful in emergency situations such as a PPH (as well as other bleeding situations) if the determination of factor XIII activity is not possible. To evaluate whether FXIII replenishment reduces blood loss is the focus of ongoing studies.

Management of anticoagulation and factor XIII replacement in a patient with severe factor XIII deficiency and recurrent venous thromboembolic disease: case report and review of literature

Background

Thrombotic events in congenital factor (F)XIII deficiency are extremely rare. To our knowledge, we describe the first case of severe congenital FXIII deficiency associated with recurrent venous thrombotic events.

Key Clinician Question

How to deal with anticoagulation treatment in patients with severe FXIII deficiency?

Clinical Approach

The patient was treated with rivaroxaban and plasma-derived FXIII substitution therapy as prophylaxis without bleeding complications. We aimed at FXIII trough levels of 50% during the loading doses of rivaroxaban, then 30% during the maintenance dose of rivaroxaban, and finally 20% during the long-term use of prophylactic dose of rivaroxaban.

Conclusion

Treatment of thrombotic events with rivaroxaban in patients with severe bleeding disorders seems to be safe, requiring an adaptation of the intensity of the replacement therapy.

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.

Clinical Validation of an Automated Fluorogenic Factor XIII Activity Assay Based on Isopeptidase Activity

Hereditary factor XIII (FXIII) deficiency is a rare autosomal bleeding disorder which can cause life-threatening bleeding. Acquired deficiency can be immune-mediated or due to increased consumption or reduced synthesis. The most commonly used screening test is insensitive, and widely used quantitative assays have analytical limitations. The present study sought to validate Technofluor FXIII Activity, the first isopeptidase-based assay available on a routine coagulation analyser, the Ceveron s100. Linearity was evidenced throughout the measuring range, with correlation coefficients of >0.99, and coefficients of variation for repeatability and reproducibility were <5% and <10%, respectively. A normally distributed reference range of 47.0–135.5 IU/dL was derived from 154 normal donors. Clinical samples with Technofluor FXIII Activity results between 0 and 167.0 IU/dL were assayed with Berichrom^® FXIII Activity, a functional ammonia release assay, and the HemosIL^™ FXIII antigen assay, generating correlations of 0.950 and 0.980, respectively. Experiments with a transglutaminase inhibitor showed that Technofluor FXIII Activity can detect inhibition of enzymatic activity. No interference was exhibited by high levels of haemolysis and lipaemia, and interference by bilirubin was evident at 18 mg/dL, a level commensurate with severe liver disease. Technofluor FXIII Activity is a rapid, accurate and precise assay suitable for routine diagnostic use with fewer interferents than ammonia release FXIII activity assays.

A Collection of Jewels

The authors of this issue of Hämostaseologie-Progress in Haemostasis on "PROGRESS AND PITFALLS IN LABORATORY HEMOSTASIS DIAGNOSIS: " were asked to write conceptual reviews, enucleating the quintessence of their subjects in order to share it with a wide audience. All performed a masterful job and you can now enjoy a collection of jewels, each with its peculiar character, which are presented in five "invisible" sections.