ELISA test for heparin induced thrombocytopenia

Eindelijk beschikbaar: IgG-Antistoffen Test voor coronavirus. Geen sneltest. Bestel nu! Zinvolle bloedtest voor IgG-antistoffen met behulp van de erkende ELISA-methode Heparin-induced thrombocytopenia (HIT), without or with thrombosis, is an important cause of recognize that a positive PF4-H ELISA test only indicates the presence of antibodies specific for PF4-heparin complexes and is not intended for diagnosis of the clinical entity, HIT. It is important to make Heparin-induced thrombocytopenia (HIT) is a serious complication of heparin therapy. Limited data are available regarding repeat HIT antibody testing after an initial negative test. We conducted a retrospective study to determine the utility of repeat testing. Heparin antibodies were detected using the GTI-PF4 enzyme-linked immunoabsorbent. Background: Immunoassays are crucial in the work-up of patients with suspected heparin-induced thrombocytopenia (HIT) and rapid tests have been recently developed. However, comparative data on diagnostic accuracy, reproducibility, and analytical costs of different immunoassays in clinical practice are limited Heparin Induced Thrombocytopenia (HIT) Aniara offers standardized ELISA Methods optimized for the detection of Heparin-dependent Antibodies. Our kits provide: Strong correlation with platelet aggregation test and measurement of Anti H PF4 Antibodies. Efficient work flow. Standard 96-well plates and MonoStrip format available

Heparin-induced thrombocytopenia is a complication of treatment with the blood-thinner (anticoagulant) heparin that can cause low platelets in the blood and an increased risk of excessive blood clotting.This test detects and measures antibodies that may be produced by your immune system when or after you are treated with heparin Heparin-Induced Platelet Antibody. Methodology. Enzyme Immunoassay (EIA) • Radiobinding 14C Serotonin Radiolabel. Assay Category. This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA. In clinical practice, immunoassays are pivotal for the workup of patients with suspected heparin-induced thrombocytopenia (HIT). 1-4 HIT is a life-threatening complication of heparin therapy that affects a significant number of patients. 5 It is associated with a high morbidity and mortality because of a massive pro-coagulant state, with a high incidence of extensive venous and arterial. Clinical significance of a borderline titer in a negative ELISA test for heparin-induced thrombocytopenia. Am J Clin Pathol. 2003 Jan; 119(1):61-65. 12520698 LOINC® Ma

The American Society of Hematology (ASH) recommends the 4Ts clinical scoring system, which is widely used to assess pretest probability for heparin-induced thrombocytopenia (HIT). This system takes into account the severity and timing of thrombocytopenia, the presence of thrombosis or other complication(s), and the likelihood of another cause of thrombocytopenia Heparin-Induced Thrombocytopenia (HIT) Testing at ARUP Laboratories. Heparin-induced thrombocytopenia (HIT) is a complication of heparin therapy. HIT is characterized by a 30-50% decrease in platelet count and an increased thrombotic risk due to platelet activation. Without treatment, up to 50% of patients can experience thrombotic events This ELISA assay detects the presence of IgG antibodies to heparin-platelet factor 4 (PF4) complexes. Most cases of heparin-induced thrombocytopenia (HIT) are caused by IgG antibodies to heparin-PF4, rather than IgA or IgM antibodies. Negative results have a good negative predictive value for HIT, although rare false-negative results may occur

Heparin-Induced Thrombocytopenia: The Dark Side of a Common Anticoagulant Often used as an initial test High sensitivity for HIT, inexpensive, simple to perform, fairly good turnaround Detectability of the antibodies precedes thrombocytopenia A negative ELISA indicates no antibodies and excludes HIT as th Heparin-induced thrombocytopenia (HIT) is a potentially fatal complication of heparin therapy. Early recognition and intervention are crucial in reducing associated morbidity and mortality. Evaluation for HIT involves both clinical assessment and laboratory tests. Clinical assessment using 4T Score is important in determining probability of HIT The following guideline is intended to guide the management of heparin induced thrombocytopenia and includes recommendations for diagnosis and treatment agents. ELISA test first2 4.1 The optical density (OD) of the ELISA can identify the probability of HIT2 (Class IIa, Level C

New Heparin-Induced Thromboctyopenia (HIT) Screening Test Method By Alexis • June 15, 2018 June 15, 2018 Beginning May 1st, the Core Lab will transition from the current ELISA anti-PF4/heparin antibody test to a latex immunoturbidimetric assay (LIA) performed on the TOPS coagulation analyzer Results are reported as: 1) Heparin-induced thrombocytopenia (HIT) enzyme-linked immunosorbent assay (ELISA) OD; 2) Heparin inhibition (%); 3) Interpretation. Typical patterns of results and interpretations are depicted in the following table. Interpretive comments will also accompany test reports, when indicated Heparin induced thrombocytopenia (HIT): ELISA for heparin:PF4 antibodies. An indirect ELISA is employed for immunological detection of HIT antibodies. HIT antibodies are captured by bound platelet factor 4 (PF4)-polyvinylsulphate complexes, which expose the same cryptic epitope in PF4 as that when bound to heparin

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Immunoassay only (ex. HIT PF4/heparin ELISA) Functional test only (ex. serotonin release assay) Immunoassay, and if positive then perform functional test. Describe a diagnostic algorithm for patients with suspected heparin-induced thrombocytopenia (HIT) 4Ts score, immunoassay, functional assay. for exclusion of clinical type II heparin-induced thrombocytopenia (HIT-II). Because up to 10% of patients with clinical heparin-induced thrombocytopenia (HIT) may have a negative H/PF4 antibody ELISA result, a negative H/PF4 antibody ELISA result does not exclude the diagnosis of HIT when clinical suspicion remains high Greinacher A., Amiral J., Dummel V., Vissac A., Kiefel V., Mueller-Eckhardt C. Laboratory diagnosis of heparin-associated thrombocytopenia and comparison of platelet aggregation test, heparin-induced platelet activation test, and platelet factor 4/heparin enzyme-linked immunosorbent assay. Transfusion

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A platelet factor 4/heparin enzyme-linked immunosorbent assay (ELISA) test was ordered in 131 patients. In total, 110 patients had a low 4Ts score (0-3), and of these 103 had a negative ELISA result. In patients with a low 4Ts score, 0 (0%) of 110 had an optical density value >1.0 Detectable in PF4/polyanion and PF4 enzyme-linked immunosorbent assay (ELISA) and in functional assays. Cause platelet activation. Not heparin dependent (not induced by heparin exposure; do not require heparin for detection in in vitro platelet activation assays). This is a major difference from antibodies found in heparin-induced. Laboratory diagnosis of heparin-associated thrombocytopenia and comparison of platelet aggregation test, heparin-induced platelet activation test, and platelet factor 4/heparin enzyme-linked immunosorbent assay. Transfusion34:381-385 Results: A platelet factor 4/heparin enzyme-linked immunosorbent assay (ELISA) test was ordered in 131 patients. In total, 110 patients had a low 4Ts score (0-3), and of these 103 had a negative ELISA result. In patients with a low 4Ts score, 0 (0%) of 110 had an optical density value >1.0

  1. Chan M, Malynn E, Shaz B, et al. Utility of consecutive repeat HIT ELISA testing for heparin-induced thrombocytopenia. Am J Hematol. In press. Shelat SG, Tomaski A, Pollak ES. Serologic results in >1000 patients with suspected heparin-induced thrombocytopenia. Clin Appl Thromb Hemost. OnlineFirst, published on September 25, 2007 as doi:10.1177.
  2. e whether the titer of the initial negative result correlated with the likelihood of obtaining a positive test result in repeated testing
  3. The next evolution in Heparin-Induced Thrombocytopenia (HIT) diagnostics, Versiti's P-Selectin Expression Assay - PEA, is now available for clinical order. When compared to the current 'gold-standard' SRA, the PEA is able to: detect more patients with HIT antibodies; and. boasts a faster analytical time, resulting in an industry-leading.
  4. The test is an ELISA (enzyme-linked immunosorbent assay) which looks for antibodies to the heparin-platelet factor 4 complex and interpretation of results is based on clinical probability score and optical density. The test has a high negative predictive value and a negative result excludes a diagnosis of HIT

Utility of consecutive repeat HIT ELISA testing for

  1. Heparin Induced Thrombocytopenia: Sensitivity and Specificity. Introduction: Also known as HITT (heparin induced thrombocytopenic thrombosis) because of its predilection for causing thromboses. Note that these can be arterial or venous, though DVT is most common. Occurs 5-14 days after exposure, unless patient has been exposed to heparin in the.
  2. Reference Range: Results are reported as: 1) Heparin-induced thrombocytopenia (HIT) ELISA Optical Density (OD); 2) Heparin inhibition (%); 3) Interpretation. Typical patterns of results and interpretations are depicted in the following table. Interpretive comments will also accompany test reports when indicated. Result Field HIT ELISA OD Heparin
  3. The HIT expert probability (HEP) score: a novel pre-test probability model for heparin-induced thrombocytopenia based on broad expert opinion. J Thromb Haemost. 2010 Sep 20. pp. 1538-7836
  4. False-positive anti-PF4 ELISA results have also been attributed to cross-reactivity to antiphospholipid antibodies. 5. Question 6. Are the tests offered as a reflex or panel? Quest Diagnostics offers both tests individually, together as a panel, and as a reflex (a positive heparin-induced platelet antibody reflexes to SRA)
4T Scoring System

Rapid immunoassays for diagnosis of heparin-induced

  1. Testing (ELISA) or Serotonin Release Assay (SRA) 4. Consider other causes of thrombocytopenia SCORE 4‐5: Intermediate Probability CALCULATE PRE‐TEST PROBABILITY FOR HIT USING THE 4T SCORE Category 2 points 1 point 0 points Thrombocytopenia Platelet count fall > 50% AN
  2. e HIT, impedance aggregometry using the Multiplate analyzer (MEA) as heparin-induced aggregation technique and the Technozym HIT IgG ELISA test were used. The MEA method uses sensitization of donor platelets with patient plasma in the presence of heparin at a concentration of 0.5 IU/mL
  3. Heparin-induced thrombocytopenia is an uncommon condition mediated by anti-PF4 platelet-activating antibodies that typically begins 5-14 days after heparin initiation. Overall, greater risk is associated with unfractionated heparin than with low-molecular-weight heparin.[1][1] The platelet coun
  4. This test is performed to detect antibodies that develop in some people who have been treated with heparin. It is used to help establish a diagnosis of immune-mediated heparin-induced thrombocytopenia (HIT type II) in someone who has a low platelet count (thrombocytopenia) and excessive clotting (thrombosis).. Heparin is an anticoagulant used to treat blood clots
  5. Keywords: Heparin-dependent platelet Ab. Description: Heparin-induced thrombocytopenia investigation is also known as HITTS (heparin-induced thrombotic thrombocytopenia syndrome) screen. Specimen: 5 mL blood in plain tube or 4.5 mL blood added to 0.5 mL citrate. Method: Standard tests fall into 2 categories: 1
  6. Heparin-induced thrombocytopenia (HIT) is an immune-mediated syndrome of thrombocytopenia and thrombosis as a result of heparin exposure. HIT is the most common type of drug-induced, immune-mediated thrombocytopenia and is associated with high morbidity and mortality if undiagnosed. The wide use of heparin in hospitalised patients demonstrates that HIT can develop in patients receiving the.

The PF4 ELISA test was negative in the other eight patients, which made the diagnosis of heparin-induced thrombocytopenia unlikely. 12 A PF4 ELISA test 15 performed at a later date on stored serum. the diagnosis of heparin-induced thrombocytopenia in two clinical settings . J Thromb Haemost . 2006 ; 4 ( 4 ): 759 - 765 • Pouplard C , Gueret P , Fouassier M , et al . Prospective evaluation of the 4Ts score and particle gel immunoassay specific to heparin/PF4 for the diagnosis of heparin-induced thrombocytopenia [see comment] .

HIT Assay ELISA Kits Aniara Diagnostic

Heparin-induced thrombocytopenia (HIT) is an adverse reaction to the administration of heparin due to the activation of the platelets by the immunoglobulin G (IgG) antibody-platelet factor 4 (PF4)/heparin immune complex. Since the clinical outcome is uncertain (as it could be associated with significant morbidity and sometimes death), an early diagnosis and appropriate treatment are necessary This test has a high sensitivity (greater than 97 percent) but a lower specificity (74 to 86 percent) because of the presence of platelet factor 4 antibodies in patients without heparin-induced. ID-PaGIA Heparin/PF4 Antibody Test (Kit) Description: Rapid test for the exclusion of heparin induced thrombocytopenia (HIT). (Id-n°: 45580) Configuration: Reagent 1: Red polystyrene particles coated with human platelet factor 4 and heparin. Reagent 2: Gel card with anti-human-IgG. Negative and positive controls. Principl Reagents for detection of Heparin Induced Thrombocytopenia (HIT) Standardised ELISA method optimised for the detection of Heparin-dependent antibodies IgG in human plasma, serum or any biological fluid, allowing confirmation of HIT/HITT diagnosis or its clinical suspicion. Please contact your local distributor for more information

Heparin-induced Thrombocytopenia PF4 Antibody Lab Tests

Useful For. Detection of IgG antibodies directed against heparin/platelet factor 4 complexes that are implicated in the pathogenesis of immune-mediated type II heparin-induced thrombocytopenia, spontaneous heparin-PF4 IgG antibody (HIT) and thrombocytopenia and thrombosis occurring after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) adenovirus vector vaccin Heparin-induced thrombocytopenia Immune thrombocytopenic purpura* liver function tests (AST/ALT > 2, GGT), ELISA test for presence of platelet factor 4 antibodies Immediate withdrawal o The condition is similar to heparin-induced thrombocytopenia. Specific risk factors for VITT have yet to be determined given the extremely low case count, though presentation seems to appear between 5-28 days post vaccination. Detection of the PF4 antibodies can be done using a HIT ELISA test, but not reliably with other HIT laboratory tests Theodore E. Warkentin, William E. Dager, in Chemistry and Biology of Heparin and Heparan Sulfate, 2005 B Heparin-Induced Thrombocytopenia Antibody-Induced Platelet Activation. Only anti-PF4/heparin antibodies of IgG class have the potential to activate platelets (22, 23).This is because platelet activation occurs when the platelet FcγIIa receptors are occupied by IgG antibodies that recognize.

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Heparin-Induced Thrombocytopenia Panel Test Detail

  1. Introduction Heparin-induced thrombocytopenia (HIT) is an acute, immune-mediated process that may result in life-threatening thrombosis. HIT is caused by platelet-activating, heparin-dependent antibodies, who form complexes of heparin together with either platelet factor-4 (PF-4) (most of the clinical cases), interleukin-8 (IL-8) or neutrophil-activating peptide 2 (NAP-2)
  2. Heparin-induced thrombocytopenia (HIT) is a severe complication that can occur in patients exposed to any form or amount of heparin products. A fall in platelet counts and a hypercoagulable state characterize HIT. Patients who experience HIT may also develop thromboembolic complications that are associated with significant morbidity and mortality
  3. VITT is a rare condition of thrombocytopenia and thrombosis following AstraZeneca COVID-19 vaccine. VITT presents similar to heparin-induced thrombocytopenia (HIT) but without prior heparin exposure. ELISA tests for PF4-heparin antibodies along with nonheparin anticoagulation are important diagnostic/treatment approaches
  4. Many patients may have thrombocytopenia for to reasons other than heparin, such as sepsis, bleeding, and extracorporal circulation. Definitive diagnostic tests (14 C-serotonin release assay, platelet aggregation test, heparin-induced platelet activation test, and enzyme-linked immunosorbent assays) may not be readily available. We developed a.
  5. Greinacher A, Amiral J, Dummel V. Laboratory diagnosis of heparin-associated thrombocytopenia and comparison of platelet aggregation test, heparin-induced platelet activation test and platelet factor 4/heparin enzyme linked immunosorbent assay. Transfusion 1994; 34: 381-5. PubMed Article CAS Google Scholar 37
  6. Summary. The natural history of heparin‐induced thrombocytopenia (HIT) in the absence of thrombosis was previously established using functional assays for confirmation of diagnosis (e.g. 14C serotonin release assay). An enzyme‐linked immunosorbent assay (ELISA) that detects the presence of antibodies directed against the heparin-platelet factor‐4 (PF4) complex has largely replaced.
  7. Distribution and correlation of 4Ts scores and heparin-induced thrombocytopenia (HIT) enzyme-linked immunosorbent assay (ELISA) screening test results. Pretest probability of low, intermediate, and high risk for HIT correlate with 4Ts score of 0-3, 4-5, and 6-7, respectively. 2 , 10 Positive and negative screening test results are indicated.

Diagnosis of Heparin-Induced Thrombocytopenia Karen A. Moser, MD Heparin-induced thrombocytopenia (HIT) is a complication seen in approximately 1%-3% of Many laboratories use commercial enzyme-linked immunosorbent assay (ELISA) kits to detect testing is recommended for definitive diagnosis.3,5,6 Functional tests, such as the serotonin. The heparin-induced platelet aggregation test on micro-ELISA plates demonstrates greater reliability and correlation with the SRA than the platelet aggregation test.82 This test is based on the visual evaluation of the aggregation of washed platelets from different donors in the presence of heparin utilizing a magnetically shaken microplate Heparin-induced thrombocytopenia (HIT) is a life-threatening immune response to heparin (and its derivatives) that is associated with a high risk of thromboembolic complications; a risk that could increase with delay in diagnosis or increase in heparin dose (to treat unrecognized HIT-associated thrombosis), o 4Ts score versus platelet factor 4 (PF4)/heparin enzyme-linked immunosorbent assay optical density. The serotonin release assay (SRA) is used as the gold standard where SRA ≥20% release is considered positive for heparin-induced thrombocytopenia PubMed journal article: Laboratory diagnosis of heparin-associated thrombocytopenia and comparison of platelet aggregation test, heparin-induced platelet activation test, and platelet factor 4/heparin enzyme-linked immunosorbent assay. Download Prime PubMed App to iPhone, iPad, or Androi

Diagnostic value of immunoassays for heparin-induced

The identification of platelet factor 4 (PF4) as the target component, allowed the design of an ELISA assay for the diagnosis of heparin induced thrombocytopenia. This assay incorporates the use of coated wells with PF4 complexed with heparin Heparin-induced thrombocytopenia is a clinical test but needs to be supported and confirmed by supporting confirmatory laboratory tests. These diagnosis includes the following Normal count of the platelets before the commencement of the heparin Onset of thrombocytopenia within 5-10 days after starting the heparin treatment The 4Ts for the diagnosis of heparin-induced thrombocytopenia (HIT) is a tool developed to help clinicians rule out HIT in patients who develop thrombocytopenia in the clinical setting. Included patients being evaluated for thrombocytopenia or suspected HIT in two clinical settings: inpatients at Hamilton General Hospital (HGH) in Canada and. Diagnosing and treating Heparin Induced Thrombocytopenia (HIT) represent a challenge for many clinicians. STic Expert® HIT is a significant step forward in HIT diagnosis. Patients with HIT have a very high thrombosis risk. They require alternative anticoagulant treatments which increase the bleeding risk. In the absence of a rapid and reliable. Heparin-induced thrombocytopenia (HIT) is a complication of heparin therapy and is characterized by two types. 1 HIT I is a benign, mild thrombocytopenia, which usually occurs within 2 days after heparin administration. Because the platelet count normalizes even with continued heparin therapy, it is not associated with increased thrombotic risk

150075: Heparin-induced Platelet Antibody (HIPA) Labcor

Identification of patients with heparin-induced thrombocytopenia is encumbered by false positive enzyme-linked immuno assay (ELISA) antibody results, therefore a serotonin release assay (SRA) is used for confirmation. Recently, several studies have demonstrated that increasing the optical density (OD) threshold (currently at 0.4) of the antibody test enhances the positive predictive value Clinically, type II HIT displays thrombocytopenia after 5 to 10 days of heparin therapy, and the platelet count decreases approximately 30 to 50%, decreasing to less than 100 X 10 3 /mm 3, but usually not falling below 10 to 20 X 10 3 /mm 3. Type II HIT is more severe because of the increased risk of thrombotic events, occurring in 30 to 80% of. HIT Overview. Heparin-induced thrombocytopenia (HIT) is a dangerous complication of heparin exposure. In HIT, the body creates an autoantibody against the complex of platelet factor 4 bound to heparin. The anti-PF4 autoantibodies can activate platelets and cause life- and limb-threatening thrombosis in arteries and veins The diagnosis of heparin-induced thrombocytopenia (HIT) may be affirmed by demonstrating heparin-dependent anti-platelet antibodies using the 14C-serotonin release assay (SRA). In this study, results of the SRA was compared with the recently described platelet factor 4 (PF4)/heparin enzyme-linked immunosorbent assay (ELISA) Pouplard C, Amiral J, Borg JY, et al. Decision analysis for use of platelet aggregation test, carbon 14-serotonin release assay, and heparin-platelet factor 4 enzyme-linked immunosorbent assay for diagnosis of heparin-induced thrombocytopenia

Heparin-Induced Thrombocytopenia Differential Diagnosis of Thrombocytopenia Estimating Pretest Probability of HIT (4Ts) Anti-PF4/heparin antibody test for confirmation 4. Avoid platelet transfusion 5. Await platelet recovery before initiation of warfarin PF4/Heparin complex using ELISA - commercial PF4/polyanion EIA assay is widely. The heparin-induced thrombocytopenia expert probability (HEP) score is a tool that can potentially aid in diagnosing patients with suspected HIT, and to avoid expensive HIT workups in some patients. The HIT Expert Probability (HEP) Score is a tool developed based on broad expert opinion to help clinicians rule out HIT Heparin-induced thrombocytopenia (HIT) has three characteristic features that can distinguish it from other causes of thrombocytopenia. [] First is the timing of the onset of thrombocytopenia; in most patients with HIT, the platelet count decrease begins from days 5 to 14 of heparin treatment Heparin-induced thrombocytopenia (HIT) is a potentially life and limb threatening, immune-mediated, pro-thrombotic disease resulting from an interaction between platelets and antibodies to platelet factor 4 (PF4)/heparin complexes [1-3].Thrombocytopenia is common in critically ill patients, making the diagnosis of HIT challenging [4-6].To assist in the diagnosis of HIT, a scoring system. HEPARIN-INDUCED THROMBOCYTOPENIA (HIT) There are two main types of tests for HIT: 1) immunologic assays which detect antibodies to PF4/heparin complexes (e.g. enzyme-linked immunosorbent assay [ELISA], particle gel immunoassay, latex particle agglutination assay), and

Heparin-Induced Thrombocytopenia - HIT Choose the Right Tes

Heparin-induced thrombocytopenia (HIT) is a prothrombotic immune drug reaction caused by platelet-activating antibodies that in most instances recognize platelet factor 4 (PF4)/polyanion complexes. Platelet activation assays (i.e., functional assays) are more specific than immunoassays, since they are able to discern clinically relevant heparin-induced antibodies Heparin exposure may be minimal (heparin - coated catheter) Note: up to 8% of heparinized patients have antibody without symptoms, 1 - 5% have thrombocytopenia, 1 / 3 of these develop arterial or venous thrombosis, 20 - 30% of these die and 20 - 30% become disabled. Affected patients usually have reduction in platelet count within 4 - 20 days. Heparin. -induced. thrombocytopenia. (HIT; formerly called type 2 HIT) is an immune-mediated prothrombotic disorder characterized by a sudden drop in. platelet count. (typically > 50% from baseline) in a patient receiving. heparin-containing products. . It typically occurs within 5-10 days of Heparin-induced platelet aggregation vs platelet factor 4 enzyme-linked immunosorbent assay in the diagnosis of heparin-induced thrombocytopenia-thrombosis. Am J Clin Pathol . 1997 Jul. 108(1):78-82. [Medline] Platelet activation assays have serum incubated with test platelets and may measure secretion of radioactive serotonin, previously taken up by the platelets. Clinical significance of a borderline titer in a negative ELISA test for heparin-induced thrombocytopenia. Refaai MA, Laposata M, Van Cott EM

(PDF) Diagnosis and management of heparin-induced(PDF) Heparin-induced thrombocytopenia among patients of aPathology Outlines - Heparin induced thrombocytopenia

HIT, heparin induced thrombocytopenia. ELISA, enzyme linked immunosorbent assay. LIA, latex immunoturbidometric assay. CLIA, chemiluminescent immunoassay. Lay Summary A number of large laboratories test for HIT antibodies using the ELISA method in Ontario, but only one laboratory in Canada performs confirmatory functional testing (the. aggregation test, heparin-induced platelet aggregation test and platelet factor 4/heparin enzyme-linked immunosorbent assay. Transfusion. 1994;34:381-385. Chong BH, Burgess J, Ismail F. The clinical usefulness of the platelet aggregation test for the diagnosis of heparin-induced thrombocytopenia. Thromb Haemost. 1993;69:344-350 From Ginger Weeden, MLS (ASCP)cm, Bio-Rad Laboratories: George, What heparin-induced thrombocytopenia with thrombosis (HIT) testing is available in the US?I'm wondering how many manufacturers there are. Thanks for any information. Hi, Ginger, and thanks for your question. All the C14 serotonin release assay methods (washed platelets) available from reference labs are laboratory-developed tests Thus, unnecessary testing Therapeutic 0.004 12.779 2.278-71.685 in patients without clinical suspicion of HIT appears to yield false positive results not only with ELISA (50%) HIT, heparin-induced thrombocytopenia; OD, optical density Inpatients at participating clinical centers who have a diagnosis of isolated Heparin-Induced Thrombocytopenia (HIT), determined by a fall in platelet count after heparin treatment and a positive Platelet Factor 4 (PF4)-heparin Enzyme-Linked ImmunoSorbent Assay (ELISA) test