Partial Thromboplastin Time Test Research Articles

Evaluation of the analytical performance of the Sysmex CS-2500 automated blood coagulation system

The aim of this study was to evaluate the analytical performance of the two new CS-2500 automated systems recently acquired by the laboratory. These are Sysmex automated systems that perform multiparametric haemostasis tests based on coagulometric, chromogenic and immunological principles with an optical detection system. The aim of this study was to evaluate their performance for prothrombin time (PT) and activated partial thromboplastin time (APTT) tests. Comparability results with the CS-2100 department's previous automated system showed high agreement between the systems, with high correlation coefficients (R ≥ 0.993). Intra-series and inter-series repeatability was less than 5%, demonstrating excellent measurement stability. The search for inter-sample contamination was negative. The automated systems showed excellent linearity over a wide range of values. All the results obtained during this evaluation point to very good analytical performance, making the CS-2500 suitable for medium- to high-activity haemostasis laboratories.

A-150 Extended Pre-Analytical Stability Validation for Coagulation Tests in Brazilian Clinical Laboratory

Abstract Background The transport of samples for coagulation tests is a challenge for clinical laboratories, due to their limited stability and short time for processing according to the manufacturer's recommendations. The objective of this study was to evaluate the possibility of extending the stability of samples collected for Prothrombin Time and Activity (PTA), activated Partial Thromboplastin Time (aPTT) and Fibrinogen tests for up to 10 hours at room temperature, in comparison with the stability described in the literature and by the manufacturer of the reagents (4 hours for aPTT, 8 hours for PTA and Fibrinogen). We verified the acceptability of the samples with a longer period between collection and analysis, including its impact on the clinical management Methods Four tubes of 3.2% sodium citrate from 40 volunteers were analyzed at times of up to 4 h, 6 h, 8 h and 10 h. The results obtained were compared with the dosage performed within 4 hours (recommended by manufacturer) and the Total Error obtained in the analysis of the samples was evaluated. The tubes remained at controlled room temperature of 15 to 25°C and were centrifuged at 1500 g for 15 minutes. Then, the analyses were performed by coagulometric method. Results The results showed safety in the analysis of samples for coagulation tests even within 10 hours after collection at ambient temperature and were within the Maximum Allowable Total Error (Carmen Ricós): 95% of the PTA results (TE 5,3%); 92.2% of aPTT results (TE 4,5%) and 98% of Fibrinogen analyses (TE 13,6%) (Figures 1, 2 and 3). In addition, even the results that exceeded the specified Total Error showed no impact on the clinical decision. Conclusions The study demonstrated that there was no significant loss of stability for the analyses of PTA, aPTT and Fibrinogen performed on samples kept at room temperature within 10 hours after collection. Most of the results showed variation within the specified Total Error and all results showed acceptability from a medical point of view

Increased packed cell volume alters point of care viscoelastic clotting parameters in horses.

Polycythaemia and coagulopathy are identified risk factors for non-survival in critically ill horses. Assessment of coagulation is recommended for critical care monitoring but may be affected by concurrent polycythaemia. To evaluate the effects of induced polycythaemia on coagulation parameters as measured by a point-of-care viscoelastic coagulation device (VCM Vet™). Prospective interventional study. Healthy adult horses (n = 7) were given 6 mcg/kg of phenylephrine IV over 15 min to induce transient polycythaemia. Samples for packed cell volume (PCV), total solids (TS), complete blood count (CBC), activated partial thromboplastin time (PTT), prothrombin (PT) and VCM Vet™ viscoelastic testing were collected at baseline (T0), 5 min (T1) and 2 h (T2) post-phenylephrine infusion. Splenic volume was measured by transabdominal ultrasonography. VCM Vet™ and plasma-based coagulation parameters, splenic volume and haematologic values were compared within and between time points. Splenic volume decreased from T0 (11.5 ± 4.8 L) to T1 (6.1 ± 2 L, p = 0.04) and returned to baseline volume by T2 (12.1 ± 3.9 L, p = 0.8), consistent with phenylephrine-induced splenic contraction. PCV increased from T0 (37% ± 4%) to T1 (56.3% ± 5.3%; p < 0.001) and returned to baseline at T2 (41.6% ± 3.6%; p = 0.1). A10 and A20 (amplitude at 10 and 20 min, VCM units) were decreased from T0 (12.6 ± 1.6, 18.9 ± 5) to T1 (5.4 ± 1.9, 7.6 ± 2.4; both p < 0.001) and remained lower than baseline at T2 (9.3 ± 2.1, 12.7 ± 3; both p = 0.01). PT and PTT remained within reference ranges with no significant difference over time (p = 0.5 and 0.09, respectively). PCV was negatively correlated with CFT (R = -0.61, p = 0.003), A10 (R = -0.9, p < 0.001) and A20 (R = -0.87, p < 0.001). Small sample size, limited to healthy mares. Phenylephrine-induced polycythaemia was associated with hypocoagulable viscoelastic traces using the VCM Vet™ device without effect on plasma-based coagulation assessments or platelet number. Further investigation of viscoelastic testing is needed in horses with increased PCV due to clinical illness.

International Council for Standardization in Haematology (ICSH) recommendations for the performance and interpretation of activated partial thromboplastin time and prothrombin time mixing tests.

This guidance document has been prepared on behalf of the International Council for Standardization in Haematology (ICSH). The aim of the document is to provide guidance and recommendations for the performance and interpretation of activated partial thromboplastin time (APTT) and prothrombin time (PT) plasma mixing tests in clinical laboratories in all regions of the world. The following areas are included in this document: preanalytical, analytical, postanalytical, and quality assurance considerations as they relate to the proper performance and interpretation of plasma mixing tests. The recommendations are based on good laboratory practice, published data in peer-reviewed literature, and expert opinion.

Novel magnetic iron oxide-dextran sulphate nanocomposites as potential anticoagulants: Investigating interactions with blood components and assessing cytotoxicity

Examining the critical role of anticoagulants in medical practice, particularly their central function in preventing abnormal blood clotting, is of the utmost importance. However, the study of interactions between blood proteins and alternative anticoagulant nano-surfaces is still understood poorly. In this study, novel approach involving direct functionalisation of magnetic iron oxide nanoparticles (MNPs) as carriers with sulphated dextran (s-dext) is presented, with the aim of evaluating the potential of magnetically-responsive MNPs@s-dext as anticoagulants. The physicochemical characterisation of the synthesised MNPs@s-dext includes crystal structure analysis, morphology study, surface and electrokinetic properties, thermogravimetric analysis and magnetic properties` evaluation, which confirms the successful preparation of the nanocomposite with sulfonate groups. The anticoagulant potential of MNPs@s-dext was investigated using a standardised activated partial thromboplastin time (APTT) test and a modified APTT test with a quartz crystal microbalance with dissipation (QCM-D) which confirmed the anticoagulant effect. Time-resolved solid-liquid interactions between the MNPs@s-dext and model blood proteins bovine serum albumin and fibrinogen were also investigated, to gain insight into their hemocompatibility, and revealed protein-repellence of MNPs@s-dext against blood proteins. The study also addressed comprehensive cytotoxicity studies of prepared nanocomposites, and provided valuable insights into potential applicability of MNPs@s-dext as a promising magnetic anticoagulant in biomedical contexts.

Generalized Multifunctional Coating Strategies Based on Polyphenol-Amine-Inspired Chemistry and Layer-by-Layer Deposition for Blood Contact Catheters.

Blood-contacting catheters play a pivotal role in contemporary medical treatments, particularly in the management of cardiovascular diseases. However, these catheters exhibit inappropriate wettability and lack antimicrobial characteristics, which often lead to catheter-related infections and thrombosis. Therefore, there is an urgent need for blood contact catheters with antimicrobial and anticoagulant properties. In this study, we employed tannic acid (TA) and 3-aminopropyltriethoxysilane (APTES) to create a stable hydrophilic coating under mild conditions. Heparin (Hep) and poly(lysine) (PL) were then modified on the TA-APTES coating surface using the layer-by-layer (LBL) technique to create a superhydrophilic TA/APTES/(LBL)4 coating on silicone rubber (SR) catheters. Leveraging the superhydrophilic nature of this coating, it can be effectively applied to blood-contacting catheters to impart antibacterial, antiprotein adsorption, and anticoagulant properties. Due to Hep's anticoagulant attributes, the activated partial thromboplastin time and thrombin time tests conducted on SR/TA-APTES/(LBL)4 catheters revealed remarkable extensions of 276 and 103%, respectively, when compared to uncoated commercial SR catheters. Furthermore, the synergistic interaction between PL and TA serves to enhance the resistance of SR/TA-APTES/(LBL)4 catheters against bacterial adherence, reducing it by up to 99.9% compared to uncoated commercial SR catheters. Remarkably, the SR/TA-APTES/(LBL)4 catheter exhibits good biocompatibility with human umbilical vein endothelial cells in culture, positioning it as a promising solution to address the current challenges associated with blood-contact catheters.

Selected Indicators of Immunothrombosis in Apparently Healthy Nigerian Women of Different Reproductive Status

Introduction: Women are considered to be vulnerable with regards to immunothrombotic conditions. Exploring this bidirectional susceptibility across the different female reproductive phases is important for effective maternal healthcare delivery. This study assessed selected indicators of immunothrombosis between premenopausal and postmenopausal women. Methods: Equal numbers of premenopausal and postmenopausal women totaling one hundred were recruited for this comparative study. Blood sample was collected from each participant into appropriate sample bottles. Blood cell counts were carried out by haemocytometry and microscopic blood film reading. Standard manual methods were also employed for prothrombin time, activated partial thromboplastin time and relative plasma viscosity tests, while blood cell ratios were calculated. Results are expressed as Mean ±SD following student t-test analysis of data on SPSS version 22.0. Statistical significance was drawn at a p≤ 0.05. Results: The eosinophils count (0.42±0.31x109/l), monocyte count (0.05±0.05x109/l) and platelets count (150.04±46.88x109/l) were significantly higher in premenopausal women than postmenopausal women (0.29±0.27x109/l, 0.03±0.03x109/l and 132.62±38.37x109/l respectively), while a significantly higher value was observed in the relative plasma viscosity of postmenopausal women (1.74±0.17mPa/s) than the premenopausal women (1.59±0.10mPa/s). The two derived indicators of inflammation (NLR) and thrombosis (PLR) correlated positively in both premenopausal (r=0.397, p=0.004) and postmenopausal (r=0.293, p=0.039) women. Conclusion: Immune and thrombotic parameters are largely comparable in apparently healthy adult females irrespective of their reproductive phase. However, eosinophil, monocyte and platelet counts were observed to be significantly higher in premenopausal women compared to postmenopausal women.

Introduction: Women are considered to be vulnerable with regards to immunothrombotic conditions. Exploring this bidirectional susceptibility across the different female reproductive phases is important for effective maternal healthcare delivery. This study assessed selected indicators of immunothrombosis between premenopausal and postmenopausal women. Methods: Equal numbers of premenopausal and postmenopausal women totaling one hundred were recruited for this comparative study. Blood sample

Introduction: Maternal healthcare takes into consideration the immediate state of an individual woman with regards to health status and subsequent management. Anaemia is a common maternal health challenge that is affected by hormonal shifts in women. Thus, this study focused on prevalence of anaemia and iron requirement across women of premenopausal and postmenopausal phases. Methods: This study enrolled apparently healthy 100 females with equal numbers of premenopausal and postmenopausal subjects. Blood sample was appropriately obtained from each subject for assessment of red cell and iron parameters. Microhaematocrit and cyanmethaemoglobin methods were employed for the measurement of packed cell volume and haemoglobin concentration respectively, while the iron parameters were assayed by colorimetric methods. Transferrin saturation was mathematically derived. Results are expressed as Frequencies and Mean ±SD, while student t-test was used for analysis of data on SPSS version 22.0. Statistical significance was drawn at a p≤ 0.05. Results: Postmenopausal women had significantly higher values of packed cell volume (0.38 ± 0.03 l/l), haemoglobin concentration (125.50 ± 9.30 g/l), serum iron (23.17 ± 0.93 µmol/l) and transferrin saturation (36.88 ± 2.00 %) than the premenopausal women (0.37 ± 0.02 l/l, 121.44 ± 7.83 g/l, 15.53 ± 2.60 µmol/l and 20.70 ± 3.60 % respectively) while the premenopausal women had significantly higher values in total iron binding capacity (75.24 ± 3.32 µmol/l) than the postmenopausal women (62.97 ± 1.88 µmol/l. Whereas 30% of the premenopausal women were anaemic and 10% had low transferrin saturation, anaemia in postmenopausal women occurred at a prevalence of 18% and the indicators of iron need were adequate. Conclusion: This study has shown that among apparently healthy individuals, prevalence of anaemia and iron requirement are lower in postmenopausal women than premenopausal women.

Pemberian SABU (Serum Anti-Bisa Ular) untuk Kasus Gigitan Ular Awitan Lama dengan Komplikasi Disseminated Intravascular Coagulation (DIC)

Background: Snakebite is a neglected disease in subtropical and tropical countries in Asia, Africa, and Latin America. Snakebite is one of the most common venomous animal bites in the world. Case: A 34-year-old male presented with a history of snakebite two days before with a swollen left gluteus and spontaneous gum bleeding. At the emergency room, the patient was fully conscious with blood pressure of 120/80 mmHg, temperature of 36.8oC, pulse rate of 80 beats per minute, and respiration rate of 18 times per minute. Blood studies showed prolonged prothrombin time (PT) and activated partial thromboplastin time (aPTT), leucocytosis, thrombocytopenia, low hemoglobin, and elevated renal function test. The patient's condition was improved after administration of anti-snake venom, vitamin K injection, transfusion of fresh frozen plasma and packed red cells. He was discharged after three days of hospital stays. Conclusion: Antivenom is the only specific antidote to snake venom; in Indonesia, there is only one local antivenom, commonly known as SABU (serum anti-bisa ular). Inappropriate use of antivenom should be strongly discouraged. Administration of the antivenom should be accompanied by preparedness for anaphylaxis risk.

Bio-inspired liquid crystal gel induction via nano-hydroxyapatite mesogens: Viscoelastic and hemostasis regulation under bone remodeling pH and temperature control

In this work, a liquid crystal mesophase as a potential bone-repairing booster has been induced from a polyacrylic acid (PAAc) gel loaded with synthetic hydroxyapatite nanoparticles (nHA) under physiological conditions of pH and temperature that resemble the early stages of bone formation. Dynamic processes at the microscale in biological systems require a material capable of behaving following a specific order and fluency. Besides, they must fulfill conditions such as biocompatibility and good mechanical properties. Our study aimed to obtain new data about the safety, hemostasis, biocompatibility (activated partial thromboplastin time (APTT) test, prothrombin time (PT) test, lactate dehydrogenase (LDH) test, red blood cell morphology observation, hemolysis percentage) and physicochemical/mechanical behavior (Attenuated Total Reflection (ATR), Infrared spectroscopy and rheological assays) of nanoparticles, and materials built with them. Both systems have shown biocompatibility with red blood cells and adequate flow properties, demonstrating promising qualities for applicability. The formation of lyotropic liquid crystals at physiological conditions was evaluated with crossed polaroids microscope with a temperature control plate. The formation of these structures under bone remodeling conditions shows the potential application of PAAc-nHA materials. In literature, the study of materials applied as bone fillers is mainly focused on mechanical and osteoblasts compatibility assays. However, the hematological effect, consequences on the coagulation cascade, the integrity of cell membranes, and hemolysis percentage have not been addressed thoroughly. The strength of our work is focused on considering these aspects when tridimensional arrangements essential for bone formation are formed.

Hemorrhagic Activity of Cationic Starch Conjugates with Sterically Hindered Phenol after Intravenous Administration to Guinea Pigs.

Intravenous injection of cationic starch conjugated with sterically hindered phenol (terpenophenol) to guinea pigs did not increase hemorrhagic activity (in doses of 2 and 4 mg/kg) and plasma clotting time in activated partial thromboplastin time and prothrombin time tests (in a dose of 4 mg/kg) in comparison with administration of physiological saline. Intravenous injection of the cationic starch conjugate with the highest content of terpenophenol fragments (4.1%wt) in a dose of 2 mg/kg to guinea pigs leads to a decrease in hemorrhagic activity by 4 times in comparison with the control.

Selected Biomarkers of Coagulation Disturbance in Newly Diagnosed Breast Cancer Patients

Coagulation disturbance can be quite detrimental to health, whether as a primary disorder or secondary to other medical conditions. The risk of thrombosis has been previously reported in breast cancer. This case- control study purposively enrolled 50 newly diagnosed female breast cancer patients. Quick's One-stage method was used for prothrombin time (PT) and activated partial thromboplastin time (APTT) tests, while fibrin plate lysis method was used for euglobulin lysis time (ELT) assessment. Data analysis was carried out on statistical package for social sciences (SPSS) version 20.0. A p-value ≤ 0.05 was considered significant. Mean values of PT, APTT and ELT of newly diagnosed breast cancer patients were compared to values from control subjects. The ELT was significantly prolonged in the breast cancer patients compared to that of controls (p = 0.001). These measured parameters were further compared within the breast cancer group on the basis of hours of immobility per day into three categories (&lt;3 hours, 3-6 hours and &gt;6 hours). Subjects with more than 6 hours of immobility Subjects with more than 6 hours of immobility per day had significantly prolonged ELT compared to those with lesser hours of immobility. This study concludes that fibrinolytic challenge exists in breast cancer prior to commencement of treatment particularly among patients with increasing immobility.

Rapidly Resolving Orbital Pseudotumor in Systemic Lupus Erythematosus

Rapidly Resolving Orbital Pseudotumor in Systemic Lupus Erythematosus

COMPARISON OF THE IN VITRO ANTICOAGULANT ACTION OF PROTEASES SECRETED BY THE MICROMYCETE ASPERGILLUS OCHRACEUS AND CONTAINED IN SNAKE VENOM

The in vitro anticoagulant action of proteases secreted by the micromycete Aspergillus ochraceus L-1 and contained in snakes’ venoms (Protac® and RVV-X® preparations) was studied. The severity of the action of micromycete protease in relation to plasmas of humans and warm-blooded animals, as well as human plasmas de cient in certain factors of the hemostasis system, in comparison with snake proteases in reactions with chromogenic peptide substrates of activated protein C and factor X, as well as using the activated partial thromboplastin time (APTT) test. The optimal time of preincubation of the micromycete A. ochraceus L-1 protease with human blood plasma (3 min) and the concentration of the chromogenic peptide substrate of activated protein C (from 0.1 to 0.5 mg/ml) necessary for the correct determination of protein C with her help.

Effects of Horsetail, Alfalfa, Ortie, Chêne and Aleppo oak as Potential Hemostatic Agents on Laboratory Coagulation Tests

This study investigated the effect of ethanol extracts of horsetail, alfalfa, ortie, chêne and aleppo oak on blood coagulation in vitro. Extraction was performed by the maceration method. Extracts were mixed with platelet and plasma, then prothrombin time (PT), activated partial thromboplastin time (APTT) and platelet aggregation tests were conducted. Alfalfa extract had a dose-dependent effect on the PT. Ortie, and horsetail, reduced the PT significantly compared to control group. Alfalfa, horsetail, and ortie reduced the APTT, but their effect was insignificant compared to the control group. The pooled extract showed the highest effect compared to the single extracts in a dose-dependent manner. Horsetail and alfalfa induced platelet aggregation in response to arachidonic acid but not in response to collagen. In the case of ortie, no aggregation occurred regarding the arachidonic acid, and incomplete was observed in response to collagen. Interestingly, blood clotting occurred immediately after adding the chêne, aleppo oak and the pooled extract, and therefore platelet poor plasma (PPP) and platelet rich plasma (PRP) became jelly. Generally, chêne and aleppo oak, as well as pooled extract, were more effective in inducing both primary and secondary coagulation pathways via shortening the PT and APTT, and induction of platelet aggregation.

Comparison of the Two Coagulation Techniques: Thrombolyzer XRM and Diagon Coag XL.

The aim of this study was to evaluate the performance characteristics of the Thrombolyzer XRM against the Diagon Coag XL during the exchange of the coagulation analyzer. The Partial Thromboplastin Time (PTT) and prothrombin time (PT) measurements were performed by using the Thrombolyzer XRM and Diagon CoagXL analyzers. The precision, accuracy, method comparison, and reference range verification studies were performed on the Thrombolyzer XRM based on Clinical Laboratory Standards Institute guidelines. The precision study was performed with normal and pathologic controls for the PT and PTT tests, all co-efficients of variation (%) were found ≤ 2.5%. In the accuracy study, both analyzers displayed less than 6.3% and 10.8% bias for PT and PTT tests, respectively. The method comparison study demonstrated good agreement for the Bland-Altman plots for PTT and PT with a bias of -2.0 and -3.3 between each analyzer, respectively. The Passing and Bablok analysis showed no significant differences for PTT and PT between each analyzer (p = 0.65 and p = 0.33, respectively). However, there was a proportional bias for PT with a slope of 1.40 (95% CI 1.2 - 1.8). The manufacturer ranges were acceptable as a result of the reference range verification study. The routine coagulation analysis can be performed on the Thrombolyzer XRM with satisfactory precision and the obtained minor differences can be eliminated in future standardization studies.

Routine Lupus Anticoagulant Sensitive aPTT Testing Can Prevent Unnecessary LA Testing.

Even though routine screening of the general hospital population is discouraged, medical laboratories may use a "lupus sensitive" activated partial thromboplastin time test (aPTT) with phospholipid concentrations that are susceptible to inhibition by lupus anticoagulant (LA), to screen for the presence of LA. If deemed necessary, follow-up testing according to ISTH guidelines may be performed. However, LA testing is a laborious and time-consuming effort that is often not readily available due to a lack of automation and/or temporary unavailability of experienced staff. In contrast, the aPTT is a fully automated test that is available 24/7 in almost all medical laboratories and is easily interpreted with the use of reference ranges. In addition to clinical signs, the result of an LA sensitive aPTT may thus be used to lower the suspicion of the presence of LA and reduce costly follow-up testing. In this study, we show that a normal LA sensitive aPTT result may be safely used to refrain from LA testing in the absence of strong clinical suspicion.

Factor XI Deficiency Case Reports on Congenital and Acquired Hemophilia C - A Case Report

Introduction: Factor XI deficiency or hemophilia C is a very rare coagulation factor deficiency, with a global incidence of 1 in 1 million. Although it is an under-recognized entity, it can cause significant bleeding, resulting in life-threatening complications. Materials and Methods: Coagulation parameters were analyzed using a Sysmex CS-2400 coagulation analyzer. Factor XI levels were detected using Factor XI deficient plasma from Siemens. Activated Partial Thromboplastin Time (APTT) testing was performed using Actin FSL from Siemens. Results: Here, we report the two cases of Factor XI deficiency, one genetic and the other a very rare acquired deficiency due to sepsis, detected during the workup of an isolated APTT prolongation. Conclusion: Factor XI deficiency is a rare bleeding disorder that presents as prolonged isolated APTT. Careful clinical evaluation and complete coagulation workup are necessary for the efficient management of patients, which can prevent life-threatening events.

Evaluation of Coaguchek®Pro II coagulation testing device performance to assess direct oral anticoagulant action. The DOAC-CHECK study

Direct oral anticoagulants (DOAC) measurement is recommended in specific conditions. A point-of-care testing should be used in emergency to qualitatively rule out relevant DOAC concentrations. The DOAC-CHECK Study aims to evaluate whether the use of CoaguChek® Pro II (Roche Diagnostics International Ltd, Rotkreuz, Switzerland) coagulation testing device can provide reliable information in patients treated with DOAC. The study was carried out in two FCSA (Italian Federation of Thrombosis Centers) centers. We choose 3 different concentration thresholds for our analysis (30, 50 and 100 ng/mL) and by ROC curves the ideal cut-off point was selected to be the one that yielded a sensitivity of at least 95% associated with the highest possible specificity. 512 patients were enrolled. For Edoxaban and Rivaroxaban, both CoaguChek® Pro II prothrombin time (PT) and activated partial thromboplastin time (aPTT) tests showed a sensitivity &gt;95% corresponding to satisfying specificity values; negative predictive values resulted in the range 90-100%. At variance, CoaguChek® Pro II PT and aPTT tests did not seem to be useful for identifying Apixaban and Dabigatran concentrations higher than the pre-defined thresholds. Our results suggest that CoaguChek® Pro II coagulation testing device can be used to qualitatively identify relevant concentrations of Edoxaban or Rivaroxaban, but not of Apixaban or Dabigatran.

Global epidemiology of factor XI deficiency: A targeted review of the literature and foundation reports.

Hereditary factor XI (FXI) deficiency is a rare coagulation disorder that may result in excessive bleeding requiring intervention to restore haemostasis. The aim of this review was to report the current knowledge of the worldwide incidence and prevalence of FXI deficiency. A targeted PubMed search using terms related to FXI deficiency was conducted to identify studies published from April 2002 through April 2022. A manual search supplemented the electronic search. Studies were eligible for data abstraction if they reported population-based incidence proportions/rates or prevalence proportions for FXI deficiency. The electronic and manual searches returned 253 publications. After applying exclusion criteria, seven publications were included in the analysis, including a global report from the World Federation of Haemophilia (WFH). Six publications provided information on the prevalence of FXI deficiency that included 74 countries and regions. The estimated prevalence of FXI in the WFH report ranged from 0/100,000 in several countries to 55.85/100,000 individuals in the United Kingdom. Prevalence estimates in the PubMed findings ranged from .1 to 246.2/1,000,000 inhabitants with varying methods of case identification and time periods of analysis. One study estimated the incidence of FXI deficiency in Yecla, Spain at 2% of blood donors and .09% of hospital inpatients/outpatients with activated partial thromboplastin time (aPTT) tests. FXI deficiency is rare across the world, but additional steps could be taken to improve incidence and prevalence estimation, for example, development of a consistent FXI deficiency definition and incorporating genetic testing into a clinical routine to better identify and characterise cases.