Activated Partial Thromboplastin Time Results Research Articles

The influence of dead space in blood sampling needle on FVIII level and pharmacokinetic profiles in children with hemophilia

ABSTRACT Objective To investigate the influence of the dead space in disposable blood sampling needle on activated partial thromboplastin time (APTT), FVIII level and pharmacokinetic (PK) profiles in children with hemophilia. Methods Children (<18 years) with severe hemophilia A were enrolled. After three days’ washout-period, blood samples were collected at pre-dose, 1 h, 3 h, 9 h, 24 h and 48 h post-infusion. At each timepoint, two 2 mL vacuum tubes with 3.2% trisodium citrate were used. The first tube was signed as ‘non-standard’ (NS) and the second tube was signed as ‘standard’ (S). FVIII activities were evaluated by one-stage assay. WAPPS-Hemo was used to generate PK profiles like half-life time (t1/2), clearance (CL), trough level and time to 1, 2 and 5IU/dL after a dose of 50 ± 10IU/dL. The FVIII activities at 9 h and 24 h post-infusion were put into WAPPS and thus brought four combinations by true or biased FVIII level that used. Result Compared with standard-collected blood samples, prolonged APTT results (P-values < 0.01) and decreased FVIII activity (P-values < 0.05) were revealed in those non-standard blood samples. The corresponding bias was in positive relation to both APTT-S (r = 0.44, P < 0.0001) and FVIII-S level(r = 0.68, P < 0.001). The FVIII bias percentage got larger as FVIII-S level reduced (r = −0.24, P < 0.01). During the four combinations of FVIII activity at 9 h and 24 h, statistically longer t1/2, lower CL and longer time to 1, 2 or 5IU/dL were observed in 9H-S&24H-S group and 9H-NS&24H-S group. Conclusion While using vacuum tubes for clotting indicators and PK profiles, the dead space of blood sampling needle should be eliminated in advance.

False Prolongation of Activated Partial Thromboplastin Time with Aminoglycoside Antimicrobial Agents: A Case Report

BACKGROUND: Activated partial thromboplastin time (APTT) is a clotting time assay for screening bleeding tendency, evaluating coagulation factor production capacity, assessing preoperatively, monitoring anticoagulant drugs, and searching for blood coagulation abnormalities such as hemophilia and antiphospholipid syndrome. CASE PRESENTATION: Here, we present a 77-year-old male patient with dyspnea who was suspected to have a drug-resistant Pseudomonas aeruginosa infection and pulmonary mycosis. The patient had no history of bleeding tendencies or anticoagulant medication use. The laboratory test results revealed an abnormally prolonged activated partial thromboplastin time (APTT) of 120.3 s using the Coagpia® APTT-N reagent. The APTT test is frequently used to evaluate blood clotting function and assess for bleeding disorders. Prolonged APTT can indicate coagulation factor deficiencies or the presence of certain conditions such as von Willebr and disease, hemophilia, and disseminated intravascular syndrome. However, APTT standardization has not been achieved, causing discrepancies in test results due to variations in the reagents used. The prolonged APTT, in this case, was initially suspected to be caused by contamination or other artifacts, but repeat blood collections and cross-mixing tests revealed the Coagpia® APTT-N reagent as the cause of false prolongation. The reagent was changed to HemosIL SynthASil APTT, which revealed a normal APTT result. The patient had been receiving the aminoglycoside antimicrobial agent tobramycin, and the blood sample taken at the peak tobramycin level demonstrated the longest APTT time. The APTT shortened over time, corresponding to the decrease in tobramycin blood levels. CONCLUSION: Overall, this paper reports a case of false APTT prolongation due to a specific APTT reagent in the presence of aminoglycoside antimicrobial agents. The findings underscore the difficulties in standar PTT testing and the importance of considering reagent performance characteristics in result interpretations.

Coagulopathies among Patients of Diabetes Mellitus in Gujrat, Pakistan

Objective: To evaluate the behavior of coagulation-related tests like prothrombin time (PT) and activated partial thromboplastin time (APTT) in chronic diabetic patients. Study Design: Cross-sectional study Place and Duration of Study: Department of Hematology, Aziz Bhatti Hospital, Gujrat, Pakistan from 1st July 2022 to 31stDecember 2022. Methodology: One hundred and seventy nine patients were enrolled. Prothrombin time and activated partial Thromboplastin time were performed from the patient’s samples. Results: Forty four patients were with good glycemic control and 135 were with poor glycemic control. It was revealed that patients with type 2 diabetes with poor glycemic control had lower levels of PT concentration 10.95±1.67 and prothrombin time was 11.50±1.331 in good glycemic control patients (P=0.04).APTT result was insignificant with 33.40±2.889 in poor glycemic control patients and while in good glycemic control APTT 34.08±1.348 (p=0.389). Conclusion: Prothrombin time was low if diabetes is uncontrolled. Early detection of lower PT may indicate that micro or macrovascular coagulopathies are in progress. APTT analysis shows insignificant results in diabetic patients and did not find a special role in coagulopathies disorders. Keywords: Coagulopathies, Prothrombin time, Activated partial thromboplastin time, Chronic diabetic patients

Comparison between use courier transport with pneumatic tube system on the results of routine hematology test, Prothrombin Time (PPT), Activated Partial Thromboplastin Time (APTT), and potassium

Pneumatic tube system (PTS) is a transport medium that is widely used in hospitals. The samples transported via PTS would get vibrations due to changing air velocity and pressure. This unstable pressure could cause pre-analytic errors in laboratory measurements. It happened because it damages erythrocytes and lymphocytes and causes haemolysis. It has been demonstrated that these changes can alter the quality of samples and induce haemolysis by leading primarily to increase in lactate dehydrogenase (LDH) concentrations, and potassium concentration. Haemolysis is dined as the release of intracellular components of erythrocytes and other blood cells into the extracellular space of blood. It can also affect the results of in vitro platelet function test. Incorrect test results can affect the diagnosis and the treatment for patients Every hospital that uses PTS are advised to validate and investigate that PTS has the possibility of haemolysis and impacts laboratory results of blood specimens. The purpose of the study was to validate and know comparison between use courier transport with using PTS on the results of routine haematology tests, PPT, APTT, and potassium. This research was experimental research by using posttest without control. The research used statistical test which was paired t-test. The research was conducted at the Integrated Clinical Laboratory Installation of the Gadjah Mada University Academic Hospital in August – October 2020 with 30 preoperative patients. Data were analysed with Prism GraphPad 8 software. There was no significant difference between WBC, RBC, Hb, HCT, MCV, MCH, MCHC, PPT, and APTT. Moreover, there was a significant difference between the results of PLT and potassium in the samples transported via PTS and delivered by courier transport.

An international study on activated partial thromboplastin time prolongation. Part 1: Analytical results

BackgroundUnexpected prolongation of first-line coagulation tests, including activated partial thromboplastin time (APTT), should trigger further work-up by performing mixing tests to elucidate the underlying cause, direct further specific testing and clarify their possible clinical impact. The aim of our study was to assess whether methodological diversity has any impact on the APTT mixing test results and their interpretation. Material and methodsTwo lyophilized plasma samples (case 1: heparin contamination [0.5 IU/mL]; case 2: factor VIII deficiency [0.13 IU/mL]) and their respective fictional clinical cases were sent to European laboratories for APTT measurement and performance of mixing tests.Participants were surveyed about the methodology (reagents, analytical platform, reference ranges), APTT results, mixing test conditions, their classification (normal, equivocal, prolonged) and categorization of the sample (factor deficiency, presence of inhibitor, anticoagulant, unknown). ResultsA total of 269 responses were included. For case 1, all participants reported a prolonged APTT, and 91% obtained no correction in the mixing test, without differences among reagents or analytical platforms. Only 15% of them selected the presence of an anticoagulant as the single cause for the prolongation.For case 2, 99% of participants reported a prolonged APTT, while some heterogeneity in the mixing test results was found. Eighty-six percent of participants selected factor deficiency as the cause for APTT prolongation. ConclusionsMost European laboratories obtained valid results for APTT and the subsequent mixing tests, despite using different methodologies. However, their classification could be improved. Therefore, more training and periodic evaluations are recommended to harmonize protocols and ensure proper result classification and categorization.

In vitro Measurement of Anticoagulant Effect of Acacia Nilotica Aqueous Extract on Normal Human Plasma

Aims: To determine the anticoagulant effect of Acacia Nilotica aqueous extract on normal human plasma.&#x0D; Study Design: This is an experimental study.&#x0D; Place and Duration of the Study: Department of Haematology, Faculty of Medical Laboratory sciences, Alzaiem Alazhari, Khartoum – Sudan, during the period from July – August 2021.&#x0D; Methodology: A total of 20 human blood samples were collected for this study from apparently healthy subjects following ethical considerations. Samples were collected in tri-sodium citrate and platelets poor plasma (PPP) were immediately prepared by centrifugation. Aqueous solution of Acacia nilotica was prepared with distilled water (D.W), three concentrations of the solution (50%, 75% and 100%) were prepared. Prothrombin Time (PT) and Activated partial thromboplastin time (APTT) were tested by manual method before and after adding different concentrations of Acacia Nilotica solution. Statistical tests were performed by using SPSS version 16.&#x0D; Results: The results of study showed that Acacia Nilotica significantly prolonged the PT and APTT results of human plasma (P values for 50%, 75% and 100% solutions were 0.000, 0.000 and 0.000 while for APTT 0.036, 0.000 and 0.000 for PT respectively). Also the study showed no significant correlation between control and A. nilotica concentrations among coagulation profile, except a significant positive correlation between control and 75% Acacia nilotica on APPT.&#x0D; Conclusion: Acacia Nilotica solutions had anticoagulant effect in human plasma, and could be nominated as a potential preventive agent for thromboembolic diseases.

Effect of Time and Haemolysis on Prothrombin Time (PT) and Activated Partial Thromboplastin Time (APTT) Measurement on Blood Samples

Background: Coagulation, also known as blood clotting, is the process by which blood convert from a liquid to a gel, forming a blood clot. It referred to haemostasis, the stopping of blood loss from a damaged vessel, followed by repair.&#x0D; Material and methods: This was cross sectional study conducted at the albawasla medical laboratory, Khartoum, Sudan during the period August to November, 2021 and to evaluate the effect of time and hemolysis on prothrombin time and activated partial thromboplastin time tests. 50 samples (case group) were collected from the patients attending police teaching hospital and requested to the PT and APTT test in addition to that,50 apparently healthy donors with no history of any coagulation problems or any chronic disease were selected as control group. Three ml of venous blood samples were collected in container with Tri Sodium Citrate anticoagulant. The coagulation tests (PT and APTT) were performed using semiautomatic device (coagulometer machine MI).&#x0D; Results: The result of this study revealed that; when compared the measurement of PT and APTT immediately and after one hour there was insignificant differences (p. v.&gt;0.05). also when compared the measurement of PT and APTT between hemolyzed and non-hemolyzed samples there was significant differences ( p. v.&lt;0.05) in addition when compared case and control for the PT and APTT immediately, after one hour, hemolyzed and non-hemolyzed sample there was significant differences ( p. v.&lt;0.05) except the APTT hemolyzed samples and insignificant differences with age and gender ( p. v.&gt;0.05). For the correlation there was significant correlation in the case group for the PT and APTT immediately, after one hour, and hemolyzed samples.&#x0D; Conclusion: In the cases group results showed insignificant differences in the results of PT and APTT between immediate sample and after 1 hour in and significant differences in the results of PT and APTT between hemolyzed and non-hemolyzed samples, also there was insignificant differences between age and gender, immediately, after one hr. and hemolyzed sample in PT and APTT.&#x0D; Keywords: Homeostasis, hemolyzed sample, PT and APTT

Characterisation and Biological Activity of Stingray Venom (HimanturaImbricata)

Stingrays envenomation in humanswere the common accident in the marine and freshwater ecosystem. To determine such effect species Himantura imbricata have been used to elucidate Hemolytic activity, Plasma Coagulation, Fibrin coagulation, Fibrinolytic activity, Activated Partial Thromboplastin Time (APTT),and Prothrombin Time (PT) effects were studied. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Amino acid analysis by RP-HPLC, FTIR spectral analysis and SEM were carried for characterization studies. The results show the of plasma coagulation, fibrin coagulation, of this stingray venom delays the coagulation of citrated plasma. APTT and PT results showed intrinsic and extrinsic coagulation factors that were responsible in time delay when compared with the control. Moreover, these biological experiments and characterization studies aided in understanding the envenoming factors and these results might base the development of treatments for complex diseases.

Correlation of Wells Score, Prothrombin Time, Activated Partial Thromboplastin Time, Fibrinogen and D-Dimer Levels with Doppler Ultrasonography in Suspected Deep Vein Thrombosis Patients

BACKGROUND/AIM: Venous thromboembolism (VTE) occur from formation of blood clots in the veins, which are mostly composed of fibrin and red blood cells with a small component of leukocytes and platelets. Most VTE manifests as deep vein thrombosis (DVT) and pulmonary embolism (PE). The lack of availability of Doppler ultrasound in health facilities especially in remote areas, makes the diagnosis of DVT challenging. There for, history taking, physical examination and laboratory findings are very important in diagnosing DVT especially in those area where Doppler ultrasound unavailable. Based on this we study the correlation Wells scores, Prothrombin Time (PT), Activated Partial Thromboplastin Time (APTT), Fibrinogen, and D-Dimer levels with the findings on Doppler ultrasound in patients with suspected DVT in Wahidin Sudirohusodo Hospital Makassar. &#x0D; &#x0D; METHOD: The study was conducted in Department of Internal Medicine, Wahidin Sudirohusodo Hospital Makassar from 2018 to 2019. Subjects were inpatients in Department of Internal Medicine with DVT suspicion. Wells scores, PT, APTT, Fibrinogen, D-Dimer levels and Doppler ultrasound results of all subjects were recorded and then analyzed. The patient is DVT positive if confirmed by Doppler Ultrasonography. Statistical analysis was performed by descriptive statistical calculations and frequency distribution as well as the Independent-t statistical test, Chi Square test and Fisher Exact test.&#x0D; &#x0D; RESULTS: Among 38 subject, 24 were men (63.2%) and 14 were women (36.8%). We found higher Wells score, shortened PT and APTT, increased fibrinogen in subject with positive Doppler ultrasound, without a significant correlation. A significant correlation was found between increased D-Dimer levels positive Doppler ultrasound results (79.4%, p = 0.048). When Wells score is added with analysis a significant correlation was also found (80.6%, p = 0.044). &#x0D; &#x0D; CONCLUSION: A significant correlation was found between increased D-Dimer levels positive Doppler ultrasound results (79.4%, p = 0.048). When Wells score is added with analysis a significant correlation was also found (80.6%, p = 0.044).

Coagulation Parameters among Women with Obstetric Complications in Specialist Hospital Sokoto, Nigeria

Background and Aim: Obstetric complications are part of the leading causes of maternal mortality worldwide. This study was carried out to investigate the effect of complications on the Prothrombin time (PT), activated partial thromboplastin time (APTT), and platelet count (PLC). Women with obstetric complications were recruited as subjects). Pregnant women without complications were included as controls.&#x0D; Study Design: This is a case-control study.&#x0D; Place and Duration of Study: The study took place in Obstetrics and Gynaecology Department of Specialist Hospital Sokoto and the duration was six months.&#x0D; Methodology: Pregnant women aged 18–41 years (mean age 29.5 years) were recruited for the study. The determination of PT and APTT was done by manual methods using commercially prepared Agappe reagent kits, whereas PLC was done by manual methods using a haemocytometer (Improved Neubauer counting chamber). Data were analyzed using SPSS version 23.&#x0D; Results: The results of PT and APTT were significantly higher among women with obstetric complications (14.26±0.23 seconds and 31.32±0.70 second) compared to normal pregnant women (13.00 ± 0.13 seconds and 29.66±0.33) (P&lt;0.05). The PLC was significantly lower among women with obstetric complications compared to women without obstetric complications (P&lt; 0.05).Obstetric complications in subject show a significant association when compared with PT and APTT (P&lt; 0.05). The age group of subjects shows a significant association when compared with APTT (P&lt; 0.05).&#x0D; Conclusion: Findings from this study have shown that obstetric complications causes decrease in platelet count and prolongation in PT and APTT. There is need to assess the PT, APTT and Platelet count routinely for pregnant women to improve the ante-natal care in Specialist Hospital Sokoto.

Interferences between Clot in the Erythrocyte Sediment and Hemostasis Exploration.

The selection and rejection of non-conforming coagulation specimens is essential in safeguarding quality management in hemostasis laboratories that provide routine testing for bleeding and thrombotic disorders. In order to increase quality, it is important to reduce pre-analytical errors that generally account for 60 - 70% of total laboratory failure. The accidental presence of clots in vitro, in the pre-analytical phase of the coagulation, is a reason for coagulation specimen rejection, given that the reliability of test results can be adversely compromised. This study aimed to ascertain the effect of clots identified in the post-analytical phase within the blood sample sediments upon standard laboratory tests such as PT (prothrombin time) and APTT (activated partial thromboplastin time). From a total of 24,670 coagulation specimens gathered and prospectively collected and analyzed at the Haematology Laboratory of the ˮSf. Spiridonˮ Emergency County Hospital Iasi, Romania, during four months, 671 were identified with clot. Of the coagulated samples, 153 (22.80%) were considered for this study, including those specimens pinpointed with sediment clot through a post-analytical new reverification procedure. The comparative study of the PT and APTT results obtained based on the samples identified with sediment clots in relation to the actual results recorded after the repetition of the sampling, pointed out 43.93% false results for PT1 test, with a significant difference between the variances of the values at the two evaluated moments (t = 2.961, p = 0.0037). The pattern was congruent in the case of the APTT test as well, exhibiting 69.04% false results, for which the variances of values at the two evaluated moments displayed significant differences (t = 2.208, p = 0.0306). In both of the cases significantly lower mean values were noted in the second determination of PT (PT1: 33.1 ± 39.6 vs. PT2: 25.8 ± 30.5) and APTT (APTT1: 42.8 ± 42.7 vs. APTT2: 38.1 ± 26.1. Results are important as they highlight the actual interference between the clot in the erythrocyte sediment and the evaluation of the patient's hemostasis. Our results confirm that the presence of clots in the erythrocyte sediment, with no identification prior to centrifugation, significantly affect the PT and APTT analysis, their accurate results being critical for the proper diagnosis and monitoring of anticoagulant therapy.

Comparison of PPT and APTT in Pre and Post-Hemodialysis Patients as the Heparin-Exposed Effect

Evaluations on Plasma Prothrombin Time (PPT) and Activated Partial Thromboplastin Time (APTT) are required in patients with Chronic Kidney Disease (CKD) stage V to determine the risk of bleeding after hemodialysis (HD) using heparin as the anticoagulant. This study aimed to compare the results of PPT and APTT in pre and post-hemodialysis patients with minimum dose of heparin. This was an observational-analytical study with cross-sectional design. The samples were collected in HD wards of Dr. Soetomo Hospital, Surabaya. There were 50 PPT and APTT samples collected from June to August 2017. The samples were evaluated using the tool CoaDATA 501. The examination of coagulation study was conducted in Clinical Pathology Laboratory of Dr. Soetomo Hospital, Surabaya. Paired t-test and Wilcoxon signed-rank test were performed in this study. In the 50 samples, pre-hemodialysis PPT ranged between 10.2-17.6 with the mean of 12.6±2.03 seconds, while for post-hemodialysis, the range was 10.1-20.9 with the mean of 13.41±2.43 seconds. Pre-hemodialysis APPT ranged between 19.5-75.2 with the mean of 30.32±10.43 seconds, while in post hemodialysis the range was 22.21-175 with the mean of 37.52±26.40 seconds. The results of PTT evaluation in pre and post-HD showed no significant difference (p=0.083), while those of APTT showed a significant difference (p=0.035 or p&lt;0.05). Prolongation of APTT in post-HD is due to the use of heparin as an anticoagulant that increases PPT and APTT by inhibiting antithrombin III. HD procedures cause decreased activity of coagulation factors II, IX, X, XII leading to APTT prolongation in post-HD. A significant APTT prolongation was found in post-HD patients with CKD V.

The accuracy of a point of care measurement of activated partial thromboplastin time in intensive care patients

Point of care (POC) devices are increasingly being used in intensive care units to obtain faster results. Data are limited on the performance of these devices in critically ill patients, especially those on heparin infusion. The objective of this study was to assess the agreement between POC activated partial thromboplastin time (APTT) and laboratory APTT results in patients on heparin infusion and to determine its impact on the clinical decisions regarding heparin dosage. We screened all patients admitted to the intensive care unit (ICU) at St George Hospital, Sydney, over a 7-month period and enrolled those who were receiving intravenous heparin infusion. We measured APTT by two methods: bedside POC test (Hemochron Junior Signature Plus) and central laboratory method (STA analyser). We used the Bland-Altman method to test the statistical agreement between the two measurements and Cohen's kappa statistic to test the clinical agreement regarding heparin dosing decision. A total of 176 paired samples from 44 patients (mean age 63 years, 64% males, mean APACHE 18) were analysed. The mean turnaround time for the point of care APTT result was significantly shorter than the central laboratory result (5.0±0.2 min vs 64.6±2.7 min, p<0.0001). Despite the statistically significant correlation, the overall agreement tested by the Bland-Altman method was poor. The 95% limits of agreement were widest (-27.266 to 64.791) and mean percentage bias was highest (24%) for the comparison between POC APTT using citrated blood and laboratory APTT. When POC APTT results of less than 90 seconds using whole blood were compared to laboratory APTT results, the limits of the agreement became narrower (-23.243 to 28.419), and the mean percentage bias decreased to 5%. The agreement between clinical decisions regarding heparin dosage based on the two methods was poor for plain and citrated blood (kappa 0.35 and 0.11, respectively). The POC APTT results were not sufficiently accurate for use in patients on heparin infusion compared to laboratory APTT assay.

Analytical Assessment of the New Roche Cobas t 711 Fully Automated Coagulation Analyzer.

This study aimed to provide a preliminary evaluation of the analytical performance of the new Roche COBAS T 711: fully automated coagulation analyzer, which uses both liquid and lyophilized reagent cassettes. The analytical assessment included analysis of imprecision and linearity of prothrombin time (PT), activated partial thromboplastin time (APTT), and fibrinogen on COBAS T 711: analyzer. Test results of 120 routine plasma samples were also compared with those obtained using two other coagulation analyzers (Instrumentation Laboratory ACL TOP 700 and Stago STA-R MAX). The accuracy, imprecision, and comparability of manual and automatic lyophilized material resuspension were also evaluated using 200 routine plasma samples. Overall, automatic resuspension was found to be more precise than, and equally accurate as, manual reconstitution, with coefficient of variations (CV%) three- to sixfold lower compared with manual reconstitution. The analytical imprecision was found to be excellent, as attested by total CV% of 0.7% for PT, 1.7 to 1.8% for APTT, and 1.9 to 3.2% for fibrinogen. Linearity was excellent over a clinically significant range of PT, APTT, and fibrinogen values, displaying correlation coefficients comprised between 0.994 and 0.999. Methods comparison studies revealed that results of PT, APTT, and fibrinogen on COBAS T 711: are globally aligned with those obtained using identical plasma samples on IL ACL TOP 700 and Stago STA-R MAX, displaying correlation coefficients of 0.97 for PT, 0.81 and 0.88 for APTT, 0.90 and 0.94 for fibrinogen, respectively. In conclusion, the results of this preliminary evaluation demonstrate that PT, APTT, and fibrinogen on COBAS T 711: coagulation analyzer displays excellent performance for routine use in clinical laboratories.

Effect of an activated charcoal product (DOAC Stop™) intended for extracting DOACs on various other APTT-prolonging anticoagulants.

Background The aim of the study was to investigate the specificity of an activated charcoal-based product (DOAC Stop™) initially intended for the specific extraction of direct oral anticoagulants (DOACs) from test plasmas on a range of other anticoagulants. Methods Test plasmas were prepared by adding various anticoagulants to pooled normal plasma at concentrations prolonging an activated partial thromboplastin time (APTT) test by a factor of 1.5-3. These plasmas were treated with DOAC Stop™ for 5 and 20 min. Then APTTs were repeated and residual anticoagulant concentrations estimated from dose-response curves. Results The activated charcoal (AC)-based product was found to extract DOACs efficiently. It also bound the intravenous anticoagulants argatroban and lepirudin, but it had no effect on heparin, enoxaparin or danaparoid in plasma. Among other APTT-inhibiting agents that might be present in test plasmas from patients, it extracted protamine, aprotinin and polymyxin. It had no effect on annexin V, thrombomodulin, a typical lupus anticoagulant, a factor VIII antibody, activated protein C or its activator, but it did bind some cationic inhibitors of the APTT with molecular weight below approximately 30 kDa. Conclusions The AC-based product extracted DOACs efficiently with no effect on heparin-type anticoagulants. It did bind argatroban and hirudin-type anticoagulants, which might occur in plasmas from some inpatients, and APTT results obtained after its use should be interpreted after due consideration of patient medications.

How can we deal with an unexpected preoperative prolongation of the activated partial thromboplastin time (APTT)? —a real world experience

Background: This article describes a tentative diagnostic algorithm for investigating patients with unexpected prolongation of activated partial thromboplastin time (APTT), detected during preoperative laboratory testing. Methods: The study population consisted of all patients undergoing preoperative laboratory testing (thus including APTT) during a 3-month period. Whenever prolonged APTT results were observed, abnormal data were investigated according to an algorithm combining familiar history of bleeding (yes/no), personal history of bleeding (yes/no) and signs/symptoms of bleeding with results of hemostasis testing, including mixing test, lupus anticoagulant (LAC) and clotting factor assays. Results: Overall, 1,433 patients underwent preoperative APTT testing throughout the 3-month study period, 76 (5.3%) of whom had prolonged values (i.e., >36.5 s). The remaining 1,357 (94.7%) patients underwent successful surgery, without further investigation. According to the algorithm, 55/76 (72.4%) of patients with prolonged APTT were excluded from supplementary laboratory testing. In the remaining 21/76 (27.6%) patients, a mixing test was scheduled. In 5/21 (23.8%) of these patients the mixing test was positive (i.e., no normalization), so that LAC testing was planned. In all these five patients LAC testing was positive. In the remaining 16/21 (76.2%) patients, mixing test was negative (i.e., normalization), so that clotting factors assays were scheduled. Seven patients were finally diagnosed with factor (F)XII deficiency, two patients with mild FXI deficiency (i.e., FXI activity of 47% and 51%), whilst 5 had clinically insignificant decreased values of one or more clotting factors and 2 patients had no identifiable explanation for APTT prolongation. The sensitivity and specificity of the algorithm for detecting clinically significant conditions (i.e., FXI deficiencies or LAC) were 1.00 and 0.99, respectively. Conclusions: The results of this study suggest that a preoperative algorithm including clinical and laboratory data may be a reasonable and sustainable approach for identifying patients at enhanced risk of perioperative bleeding or thrombosis.

Establishment of reference intervals and transfusion criterion for Sonoclot analysis.

Sonoclot analyzer has been widely used in many countries. But the reference intervals provided by the manufacturer were derived from only 45 participants, and there was no cut-off value for transfusion for Sonoclot analysis. This study aimed to establish reference intervals and transfusion criterion for Sonoclot analysis. Volunteers were recruited from healthy Chinese adults and patients undergoing cardiac surgery. Blood samples were withdrawn from forearm vein and measured for activated clotting time (ACT), clot rate (CR), platelet function (PF), activated partial thromboplastin time (APTT), fibrinogen concentration (FIB), and platelet count (PLT). The reference intervals were determined by the nonparametric method. Cut-off values were determined by the receiver operating characteristics curve. A total of 135 healthy volunteers and 281 patients were enrolled. The 95% reference intervals were 96-195 s, 22-51 signal U/min, >1.6 for ACT, CR, PF respectively. In the 281 patients, the results of APTT, FIB, PLT, ACT, CR, and PF ranged from 20.5-300.0 s, 0.28-4.11 g/L, (19.0-387.3)×109/L, 80-514 s, 2.9-74 signal U/min, and 0.1-5.1 respectively. The cut-off values for transfusion were >208, ≤14, and ≤1.3 for ACT, CR, PF respectively. The cut-off values of Sonoclot analysis were within the manufacturer's reference intervals, while they were outside the reference intervals established in this study. The results suggested that the manufacturer's reference intervals were not suitable for Chinese. The reference intervals and cut-off values established in this study will be helpful to Chinese patients.

Activated Partial Thromboplastin Time Monitoring of Unfractionated Heparin Therapy: Issues and Recommendations.

When administering unfractionated heparin (UFH), therapeutic levels of anticoagulation must be achieved rapidly and maintained consistently in the therapeutic range. The basic assays for monitoring UFH therapy are the activated partial thromboplastin time (APTT) and/or the chromogenic antifactor Xa or antithrombin assays. For many laboratories, the APTT is the preferred standard of practice; however, the APTT is a surrogate marker that only estimates the heparin concentration. Many factors, including patient variation, reagents of the APTT, UFH composition, and concentration can influence the APTT result. This article reviews various methods to determine the heparin therapeutic range and presents recommendations for the laboratory to establish an APTT heparin therapeutic range for all sizes of hospitals.

In vitro anticoagulant activity of different processed products of Whitmania pigra by water extraction and bionic extraction

In order to determine the scientificalness of traditionally processed Whitmania pigra, water extraction method and bionic extraction method were used respectively to extract the anticoagulating active components in W. pigra hanging dry products, talcum powder fried products and wine immersing-baked products. Activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), and antithrombin activity were selected as the activity indexes to evaluate the anticoagulant activities of different processed W. pigra. Then the contents of protein in different processed W. pigra were measured by Coomassie brilliant blue method to preliminarily explain the reason of anticoagulant activity changes. When water extraction method was used, the results of APTT, PT, TT and antithrombin activity showed that the anticoagulant activities of W. pigra were decreased both in talcum powder fried products and wine immersing-baked products, and the activity order was as follows: hanging dried products> wine immersing-baked products>talcum powder fried products. This order was same as the protein content order. While when bionic extraction was used, APTT was shortened in talcum powder fried products, but all the other results indicated the anticoagulant activities of W. pigra processed products were increased, and the activity order was as follows: wine immersing-baked products>talcum powder fried products>hanging dry products. As compared with water extraction, the bionic extraction was more similar to the absorption process of W. pigra in human digestive system after oral administration and was more scientific. Therefore, the traditional processing method can not only modify the taste and smell, but also enhance the anticoagulant activity of W. pigra.

The Effect of Time and Temperature Variables on Some Routine Coagulation Tests among Subjects of African Descent in Sokoto, North Western Nigeria

This study evaluated the effects of time and temperature variables on routine Pro-thrombin Time test and Activated Partial Thromboplastin Time (APTT) test among subjects of African descent in Sokoto, North Western Nigeria. Samples of 99 subjects made up of 49 male and 50 female subjects with mean age 38.3 ± 22.3 years. Coagulation tests were performed immediately specified times after phlebotomy up to 24 hours (0, 1, 2, 3, 4 and 24 hours at room temperature of 40 degrees C. Our data demonstrate that prothrombin time and APTT results are stable for up to 2 hours, remaining constant regardless of storage conditions. Post hoc tests using Bonferroni correction revealed that there were increases in PT time from 0 hour to 4 hours (17.82 ± 0.61 seconds vs 18.30 ± 0.59 seconds, respectively), from 0 hour to 24 hours (17.82 ± 0.61 seconds vs 18.48 ± 0.59 seconds, respectively), from 2 hours to 4 hours (17.89 ± 0.58 seconds vs 18.30 ± 0.59 seconds), from 2 hours to 24 hours (17.89 ± 0.58 seconds vs 18.48 ± 0.58 seconds), which were all statistically significant (p = 0.002 and p < 0.000, p < 0.000, p < 0.000, respectively). However, the increase in PT time from 0 hour to 2 hours (17.82 ± 0.61 seconds vs 17.89 ± 0.59 seconds, respectively) and from 4 hours to 24 hours (18.30 ± 0.59 vs 18.48 ± 0.59 seconds, respectively) were not statistically significant (p = 1, p = 0.428). A repeated measure ANOVA determined that mean PTTK time differed statistically significantly between time points F (3, 291) = 119.22, p < 0.001. Post hoc tests using Bonferroni correction revealed that there were increase in PTTK time from 0 hour to 2 hours (37.86 ± 1.04 seconds vs 39.94 ± 1.07 seconds, respectively), from 0 hour to 4 hours (37.86 ± 1.04 seconds vs 42.34 ± 1.11 seconds, respectively), from 0 hours to 24 hours (37.86 ± 1.04 seconds vs 44.93 ± 1.20 seconds), from 2 hours to 4 hours (39.94 ± 1.07 seconds vs 42.34 ± 1.11 seconds), from 2 hours to 24 hours (39.94 ± 1.07 seconds vs 44.93 ± 1.20 seconds) and from 4 hours to 24 hours (42.43 ± 1.11 vs 44.93 ± 1.20 seconds), which were all statistically significant at p < 0.001). Therefore, we conclude that there are no statistically significant differences in the PT and APTT between 0 and 2 hours. A longer timing (after 2 hours) from phlebotomy collection of blood from respondents elicited a statistically significant increase in the PT and APTT result. There were no statistically significant differences in the PT and APTT result determined 4 hours and 24 hours after phlebotomy. Longer timing from collection of blood from respondents elicited a statistically significant increment/increase in the clotting time using PTTK. Our data demonstrate that PT and APTT results are stable for 2 hours remaining constant regardless of storage conditions.