scholarly journals Falsely positive heparin‐induced thrombocytopenia antibody testing in severe hyperbilirubinemia

2021 ◽  
Vol 5 (7) ◽  
Author(s):  
Daniel Egert ◽  
Vinicius Jorge ◽  
Adam Cuker ◽  
Gabor Varadi
Keyword(s):  
Antibody Testing ◽  
Heparin Induced Thrombocytopenia ◽  
Severe Hyperbilirubinemia

scholarly journals MEETING ITS MATCH: NONSPECIFIC VERSUS IGG-SPECIFIC PF4 ANTIBODY TESTING IN THE MANAGEMENT OF HEPARIN-INDUCED THROMBOCYTOPENIA

2012 ◽  
Vol 59 (13) ◽  
pp. E1897
Author(s):  
Katelyn Woods Sylvester ◽  
Kevin Anger ◽  
Lina Matta ◽  
Robert Southard ◽  
Nahal Beik ◽  
...  
Keyword(s):  
Antibody Testing ◽  
Heparin Induced Thrombocytopenia

Retrospective Cost Analysis of Testing for HIT Antibodies in a Community Hospital

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4544-4544
Author(s):  
Raimonda Goldman ◽  
Berry Ustun ◽  
Randy L. Levine
Keyword(s):  
Cost Analysis ◽  
Retrospective Review ◽  
Mayo Clinic ◽  
Community Hospital ◽  
Elisa Test ◽  
Bleeding Complications ◽  
Antibody Testing ◽  
Heparin Induced Thrombocytopenia ◽  
One Year ◽  
The Cost

Abstract Background: Heparin-Induced Thrombocytopenia is a serious, immune-mediated complication of heparin therapy. At Lenox Hill Hospital when HIT is suspected, a test for heparin associated antibodies is ordered. Like many community hospitals, Lenox Hill Hospital does not perform this test “in house”, so it is sent to a reference lab. We use the Mayo Clinic Laboratory as our reference lab. It takes about 7 days for results to come back to Lenox Hill Hospital from the Mayo Clinic Lab. Meanwhile, patients are started on Argatroban or Lepirudin infusions in order to avoid thrombosis. We performed a retrospective review of all patients suspected of having HIT in a one year period, in order to assess the cost effectiveness of sending out these tests and treating these patients with alternative anticoagulants while waiting for the test results. Methods: We performed a retrospective review of all patients who were tested for HIT Antibodies. We obtained a list of patient specimens sent to Mayo Clinic for heparin associated antibodies from January 2007 to January 2008. A list of patients placed on either Argatroban or Lepirudin infusions was also obtained for the same time frame from our Pharmacy Department. We then recorded the results for the ELISA test for the HIT antibodies from our computer system. Results: There were 150 patient samples sent for heparin associated antibody tests to the Mayo Clinic Laboratory during these 12 months. Only 12 out of 150 patient samples tested positive for HIT by ELISA. Four out of 150 tested equivocal for HIT. All the remaining reports were negative. The hospital was charged $300 for each ELISA test, so our community hospital spent $ 45,000 in one year on heparin associated antibody testing. 15 of these patients were placed on Argatroban infusion while awaiting lab results. All fifteen patients who were placed on Argatroban ultimately tested negative for HIT. Four patients were started on Lepuridin infusions. Only one of the patients on Lepuridin tested positive for HIT. In total, there were 19 patients treated with either Argatroban or Lepuridin during this 12 months period. Only one patient, out of the 19 treated patients tested positive for HIT. The 12 months cost analysis showed that 100 vials of Lepirudin were used at a cost of $158.80/vial, for a total of $15,880. The 12 months cost analysis for Argatroban showed that 15 vials were ordered each month at a cost of $985/vial for a total of $177,300. The total amount spent including testing and expectant came to $238,180.00. Only one patient truly needed to be treated with an alternative anticoagulant. Discussion: Lepirudin and argatroban are two accepted drugs for treatment of HIT. These are direct thrombin inhibitors that are given intravenously. Argatroban binds to the catalytic site of thrombin. It gets metabolized by the liver and should be dose adjusted with careful monitoring in patients with hepatic impairment. No dose adjustment is necessary in patients with renal dysfunction. Lepirudin binds to both catalytic and a fibrinogen-binding site of thrombin. It gets excreted in the urine and should be carefully monitored in patients with renal insufficiency. Both drugs can lead to bleeding complications. These drugs should be used with great caution when there is an increased risk of a hemorrhagic event. The cost of Argatroban and Lepirudin infusions was obtained from the pharmacy purchase orders. The cost of HIT antibody testing was obtained from our main labarotory. The cost of the machine at the Mayo Labarotory that is used in the Special Coagulation laboratory (DSX ELISA processing system) was $52,000. The machine was purchased prior to 2004. We concluded that our community hospital spends a total of $238,000 per year in the evaluation and expected management of heparin-induced thrombocytopenia. Conclusion: In this retrospective review of 150 patients who have had HIT antibodies testing and 19 who were started on anticoagulation therapy and have had their HIT antibodies tests sent out for HIT confirmation, only 1 had a positive result. We concluded that our community hospital spends a total of $238,000 per year in the evaluation and expectant management of heparin-induced thrombocytopenia. The hospital would save money and improve patient care if it purchased the laboratory equipment and ran the tests in-house, providing faster turn around and more accurate assessment of risk.

Suspicion of heparin-induced thrombocytopenia in internal medicine: How appropriate is the ordering of anti-PF4/heparin antibody testing?

Platelets ◽  
2014 ◽  
Vol 26 (7) ◽  
pp. 632-637 ◽  
Author(s):  
Yan Beauverd ◽  
Françoise Boehlen ◽  
Elena Tessitore ◽  
Eric Gerstel ◽  
Pierre Fontana ◽  
...  
Keyword(s):  
Internal Medicine ◽  
Antibody Testing ◽  
Heparin Induced Thrombocytopenia

scholarly journals Testing for Heparin Induced Thrombocytopenia in Hospitalized Patients: In Line with Evidence?

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 1957-1957
Author(s):  
Udhayvir Singh Grewal ◽  
Shiva Jashwanth Gaddam ◽  
Sahith Reddy Thotamgari ◽  
Tyiesha Brown ◽  
Kavitha Beedupalli ◽  
...  
Keyword(s):  
Conflicts Of Interest ◽  
Heparin Therapy ◽  
Hospitalized Patients ◽  
Antibody Testing ◽  
Drug Induced ◽  
Platelet Factor ◽  
Heparin Induced Thrombocytopenia ◽  
Clinical Probability ◽  
Test Probability ◽  
4T Score

Abstract Background: Heparin-induced thrombocytopenia (HIT) is an immune complication of heparin therapy caused by antibodies to complexes of platelet factor 4 (PF4) and heparin. Both clinical probability and laboratory testing are needed for establishing a diagnosis of HIT. The 4Ts clinical scoring system, due to a very high negative predictive value when low, offers a robust means to exclude a diagnosis of HIT. However, these strategies are under-employed in clinical practice and limited evidence indicates a high prevalence of over-testing for HIT. Methods: This retrospective analysis was conducted to identify patients who underwent heparin/PF4 antibody testing over a period of 12 months. The testing was performed using an ELISA-based IgG anti-heparin/PF4 antibody assay and an optical density (OD) of 0.4 was used as a cut-off for a positive value. Electronic medical records were reviewed for 4T score documentation, anti-PF4 results, SRA testing and 4T scores were retrospectively calculated for all the patients. SAS v9.4 (Cary, NC) was used for statistical analysis. Results: A total of 105 patients who underwent anti-PF4 antibody testing were included for analysis. Majority of the patients in our cohort were admitted in an intensive care unit setting (75/105,71.4%). On chart review, only 17 patients (16.2%) were noted to have documentation of 4T score. Based on the retrospectively calculated 4T scores, 60 patients (57.1%) had low pre-test probability, 41 (39%) had intermediate pre-test probability and 4 (3.8%) patients were noted to have high pre-test probability. Anti-PF4/heparin antibodies were positive in 9 patients, of which 5 (55.5%) patients did not undergo concomitant SRA testing. Out of 9, 4 (44.4%) had weakly positive (0.4-1.0 OD units), 2 (21.1%) had strongly positive (1.0-2.0 OD units) and 2 (21.1%) patients had very strongly positive (>2 OD units) anti-PF4 antibody titers. Out of 105 patients, SRA was tested in 11 patients (10.5%) and was noted to be positive in 1 (0.95%). Overall, 2 patients were diagnosed and treated for HIT, out of which the diagnosis was not confirmed with SRA in 1 patient (due to high pre-test probability and very strong anti-PF4 titers). In the remaining patients, sepsis (48, 46.6%) and drug-induced thrombocytopenia (29, 28.2%) emerged as the most common possible causes of thrombocytopenia. Conclusion: Among hospitalized patients, over-testing for HIT is common. Practices to promote 4T score documentation and evidence-based anti-PF4 testing may help prevent unnecessary costs associated with serological testing and costly alternate anticoagulants. To improve overall outcomes, clinicians should also attempt to identify and treat other more likely causes of thrombocytopenia, especially in patients with low pre-test probability for HIT. Disclosures No relevant conflicts of interest to declare.

scholarly journals Is Heparin Induced Thrombocytopenia Expert Probability (HEP) Scoring System Superior to 4T'S Scoring in the Diagnosis of Heparin Induced Thrombocytopenia? a Prospective Observational Study from a Tertiary Care Cardiac Centre in India

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1073-1073
Author(s):  
Amarnadh Polisetty ◽  
Nataraj KS ◽  
Hamza Yusuf Dalal ◽  
Shilpa Prabhu ◽  
Devi Prasad Shetty ◽  
...  
Keyword(s):  
Scoring System ◽  
Room Temperature ◽  
Area Under The Curve ◽  
Antibody Test ◽  
Scoring Systems ◽  
P Value ◽  
Antibody Testing ◽  
Heparin Induced Thrombocytopenia ◽  
The Difference ◽  
4T Score

Heparin-induced thrombocytopenia (HIT) is a drug-induced thrombocytopenia that results in thrombotic complications rather than bleeding.In many countries like India, the availability of functional assay for diagnosing HIT is unavailable. But with the utility of scoring systems the probability of HIT can be assessed and can guide the intervention required. Presently there are two well characterised and easily calculated scoring systems, which are the commonly used 4T scoring system and newly designed HEP score, to overcome some of the limitations of 4T`s scoring system. The 4Ts score has a negative predictive value (NPV) approaching 100%, but is limited by modest positive predictive value (PPV) and significant inter-observer variability.In this study we are comparing the two scoring systems and their relevance in the Indian scenario in patients undergoing cardiac intervention, receiving heparin. METHODS: - We recruited 100 patients with suspected HIT, for whom antibody testing was orderedat our centre (Narayana Health City, Bangalore, India) between November 2017 and May 2018. - Data were collected at baseline diagnosis in the form of clinical and laboratory data. 4T`s score and the HEP score was calculated based on the above details before the availability of antibody test. - HIT antibody testing was done using ID-PaGIA Heparin/pF4 Antibody Test Kit with control. In this 10 millilitre of serum is pippeted into the upper chamber of the appropriate microtube. Incubate the ID card at room temperature for 5mins at room temperature (18-25oc). Later centrifuge the ID-card for 10mins in the ID-centrifuge then read and records the results. - Patients were followed up daily till the discharge and complete blood picture including WBC count, development of any adverse effects including renal failure, sepsis, intra-arterial device insertion, bleeding was noted. - Area under the curve (AUC) for the receiver operating curve (ROC) of HEP and 4T scores was calculated and p value was obtained based on these curves. RESULTS: - 37 patients were HIT antibody positive out of 100 patients with suspected HIT from a patient population of 26430, who received heparin. The overall incidence of HIT in our institute is 0.14% (37/26430). - Out of the 100 suspected patients 37 were proven to have HIT by using ID-PaGIA Heparin/PF4 rapid gel agglutination assay. In this series, 91% patients had undergone cardiothoracic surgery forming the majority. Two-thirds of the study population was in the age group (41-70years). Males (61%) are more in the study than females (39%).The percentage of HIT positivity was more in females (43.5) than males (32.7%). - In 87 patients who received UFH, who presented with thrombocytopenia during their perioperative period, 30 were proven to have HIT (34.4%).We also observed during that the total leucocyte count at the nadir of platelet was higher in thr HIT positive group. However, it was not statistically significant (p-0.283) - Out of 100 patients with suspected HIT 49% expired. Of the 37 cases proven to have HIT 20 patients expired (54%). There was no statistically significant association between the occurrence of HIT and mortality ( p-value =0.438). - In this study, the areas under the curve for predicting HIT by 4T score was more than HEP score (0.754 and 0.66) with P value-0.093. As the HEP score was not superior to 4T score we have evaluated 2 subgroup analysis. - Among 36 subjects with the intra-arterial device (included in HEP score), 12 were positive for HIT (33.3%). Area under the Curve for the 4T score (0.698) was higher than that for HEP score (0.599) although the difference was not statistically significant(p-0.3906) - In this study, the incidence of renal replacement therapy (not included in HEP score)was 43%. In this patient population, 46% (n=20) are HIT positive. Among subjects on RRT, 4T score (814) had higher Area under the curve compared to HEP score (0.607) in the diagnosis of HIT positivity and the difference was statistically significant (p value 0.035). CONCLUSION The newly diagnosed HEP scoring system, which includes additional causes of thrombocytopenia was not superior to the 4T's score in this study. The inclusion of intra-arterial device in the HEP score did not make a difference in prediction of HIT. Conversely the 4T score was superior to HEP score in the evaluation of the subset of patients on renal replacement therapy, a significant cause of thrombocytopenia, which was not included in the scoring system. Disclosures No relevant conflicts of interest to declare.

scholarly journals Diagnostic Performance of Heparin-Platelet Factor 4 Antibodies in the Identification of Heparin-Induced Thrombocytopenia in Cancer Population

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4896-4896
Author(s):  
Thein H. Oo ◽  
Cristhiam Mauricio Rojas Hernandez
Keyword(s):  
Cancer Patients ◽  
Serotonin Release ◽  
Diagnostic Tools ◽  
Cancer Center ◽  
Antibody Testing ◽  
Platelet Factor ◽  
Heparin Induced Thrombocytopenia ◽  
Release Assay ◽  
Md Anderson ◽  
4T Score

Introduction: Cancer patients appear to have a higher risk of heparin induced thrombocytopenia (HIT) related complications than non-cancer patients; yet data on the performance of conventional diagnostic tools for HIT in cancer is limited. Our aim was to determine among cancer patients with a 4T score ≥ 4, the performance of the conventional cut-off for HIT antibody testing (IgG anti PF4) to discriminate between serotonin release assay (SRA) positive and negative cases. Methods: Retrospective and prospective analysis of cases (2002-2019) was performed of the electronic medical records of adult cancer patients at MD Anderson Cancer Center with suspected HIT. Cases were included in the analysis if the 4T score was ≥ 4 and investigated with IgG anti-PF4 optical density (HIT OD) and SRA. Logistic regression model and the receiver operating characteristic curves were conducted to identify the sensitivity and specificity of different cut-off points for the HIT OD to discriminate HIT cases based on the SRA status. Results: Among 50 cases, 18 were SRA positive. Median HIT OD was 1.03. At a cut-off point of 0.4, the HIT OD performed with a sensitivity of 0.89 and a specificity of 0.50 to discriminate the cases of SRA positive HIT. When the cut-off HIT OD was 1.0, the sensitivity was 0.78 with a specificity of 0.66. Conclusions: Our findings suggest that in cancer patients the performance of IgG anti-PF4 is similar to that of non-cancer patients for the identification of HIT cases. Disclosures Oo: Janssen and Janssen: Other: Research: site co-investigator ; Medical Education Speakers Network: Honoraria.

scholarly journals The Appropriateness of Heparin Antibody Testing. A Single Institution Retrospective Analysis

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3277-3277 ◽  
Author(s):  
Danny A. Landau ◽  
Nadezhda Kholodnaya ◽  
Ana CuestaFernandez ◽  
Ariel PerezPerez
Keyword(s):  
Internal Medicine ◽  
Hospital Stay ◽  
Scoring System ◽  
High Probability ◽  
Conflicts Of Interest ◽  
Length Of Hospital Stay ◽  
Low Risk ◽  
Antibody Testing ◽  
Drug Induced ◽  
Heparin Induced Thrombocytopenia

Abstract Background: Heparin-induced thrombocytopenia (HIT) is a drug-induced, immune-mediated prothrombotic disorder associated with thrombocytopenia and venous and/or arterial thrombosis.Up to 5% of patients exposed to heparin for at least one week develop HIT, and approximately 50% of them will have thrombosis. Diagnosis of HIT is suspected from the clinical picture based on the ''4 T's'' (Thrombocytopenia, Timing, Thrombosis, no other cause of platelet fall) or the HIT Expert Probability (HEP) scoring system. However, often these "4 T's" are ignored and testing is inappropriately ordered in low risk patients. This could lead to possible morbidity and increase length of hospital stay. We opted to look back at the appropriateness of testing done within our academic center. Methods/ Design: All hospitalized patients with thrombocytopenia who underwent HIT antibody testing (HIT ELISA) during February 2013 were screened using our internal electronic medical record. Patients were subdivided to low, intermediate or high pretest probability group according to the 4Ts scoring system. Appropriateness of testing was determined according ASH 2013 Clinical Practice Guideline on the Evaluation and Management of Adults with Suspected Heparin-Induced Thrombocytopenia (HIT). HIT Ab test is recommended to be tested when there is intermittent to high probability of HIT (4T's score above or equal to 4). The percentage of appropriate/inappropriate testing was calculated. The results were then subdivided by ordering physician group. Results: 120 HIT ab tests were performed during February 2013 in our institution. Only 13 patients tested had a positive HIT Ab. Internal medicine ordered the majority of these tests. Of the 120 patients tested, 7 patients had high risk and another 50 had intermediate risk as per 4T's scoring. 61 patients were low risk and should not have been tested. (Table 1) Table 1. HIT antibody test ordered per Service and probability of HIT. Service ordering test Low probability of HIT Intermediate/high probability of HIT TOTAL Internal Medicine 28 28 56 Cardiothoracic Surgery 13 11 24 Hematology Oncology 7 5 12 Cardiology 3 1 4 Surgery 1 4 5 Emergency medicine 0 1 1 Infectious disease 4 0 4 Pulmonary 0 1 1 Critical care 1 6 7 Nephrology 1 2 3 Ob Gyn 1 0 1 Family Medicine 2 0 2 TOTAL 61 59 120 Conclusions: HIT testing has been overused within our institution. Low platelets, without other signs or symptoms of typical HIT were used as a trigger for testing the antibody. This has potential to cause harm due to increased bleeding risk, increased length of hospital stay, and the potential to utilize extended anticoagulation when not necessary. Better education on the appropriateness of the test can limit the potential harm of its use. Disclosures No relevant conflicts of interest to declare.

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