Assessment of the 4Ts Pretest Clinical Scoring System as a Predictor of Heparin‐Induced Thrombocytopenia

Strutt, Jaclyn; Mackey, Jennifer; Johnson, Stephen M.; Sylvia, Lynne M.

doi:10.1592/phco.31.2.138

Cited by 30 publications

(37 citation statements)

References 27 publications

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“…10,37,38 Inter-rater agreement was assessed in only one eligible study 10 and therefore could not be addressed in our meta-analysis, but is an important potential shortcoming of the 4Ts that merits further investigation. Newer scoring models, including a revised version of the 4Ts, include more detailed and explicit itemization of clinical features in an attempt to clarify their meaning and enhance reproducibility among raters.…”

Section: Discussionmentioning

confidence: 99%

Predictive value of the 4Ts scoring system for heparin-induced thrombocytopenia: a systematic review and meta-analysis

Cuker

Gimotty

Crowther

et al. 2012

Blood

406

335

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The 4Ts is a pretest clinical scoring system for heparin-induced thrombocytopenia (HIT). Although widely used in clinical practice, its predictive value for HIT in diverse settings and patient populations is unknown. We performed a systematic review and meta-analysis to estimate the predictive value of the 4Ts in patients with suspected HIT. We searched PubMed, Cochrane Database, and ISI Web of Science for studies that included patients with suspected HIT, who were evaluated by both the 4Ts and a reference standard against which the 4Ts could be compared. Quality of eligible studies was assessed by QUADAS-2 criteria. Thirteen studies, collectively involving 3068 patients, fulfilled eligibility criteria. A total of 1712 (55.8%) patients were classified by 4Ts score as having a low probability of HIT. The negative predictive value of a low probability 4Ts score was 0.998 (95% CI, 0.970-1.000) and remained high irrespective of the party responsible for scoring,

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Section: Discussionmentioning

confidence: 99%

Predictive value of the 4Ts scoring system for heparin-induced thrombocytopenia: a systematic review and meta-analysis

Cuker

Gimotty

Crowther

et al. 2012

Blood

406

335

View full text Add to dashboard Cite

show abstract

“…Strutt et al [11] reported eight of 13 intermediate scoring patients and one of five high scoring patients with a positive PaGIA were not commenced on alternative anticoagulation. Although it appears that this may represent suboptimal management, we feel that it is likely to reflect a widely experienced difficulty in managing the often very complicated clinical scenario of potential HIT patients.…”

Section: Discussionmentioning

confidence: 99%

Egyptian experience of reliability of 4T's score in diagnosis of heparin induced thrombocytopenia syndrome

Tawfik¹,

Hegazy²,

Hassan³

et al. 2011

Blood Coagulation &Amp; Fibrinolysis

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To evaluate the utility of the 4Ts clinical scoring system as a pretest probability method for detection of heparin-induced thrombocytopenia (HIT). Medical and surgical inpatients and outpatients at Kasr El Eini hospital. This single-centre series of 50 HIT testing referrals assessed combination of clinical score (thrombocytopenia, timing, thrombosis, other causes of thrombocytopenia not evident; 4T's), Heparin platelet factor 4 (H-PF4) rapid particle gel immunoassay (PaGIA) and 14C serotonin release assay (SRA) to develop a practical and well tolerated diagnostic strategy for HIT. Sixteen patients (32%) had a low 4T's score, 26 (52%) had an intermediate score and only eight (16%) had a high score. A positive H-PF4 by PaGIA was seen in seven patients (14%). As might be anticipated, the likelihood of obtaining a positive H-PF4 by PaGIA increased with an increasing clinical score, with positive H-PF4 by PaGIA results in low, intermediate and high scoring patients of 6.25, 7.7 and 50%, respectively. The positive predictive value of a positive PaGIA was 92%. The negative predictive value was 100%. Five patients (10%) in our cohort had a positive SRA. All patients with a positive SRA were included in the intermediate (two of 26 patients, 7.7%) or high (three of eight patients, 37.5%) score groups. The negative predictive value of a low 4T's score was 100%, effectively ruling out HIT. A low 4Ts score supports low probability of HIT based on the results of the PaGIA and SRA. Overall, the interrater reliability of the scoring system was fair.

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“…Unfortunately, the diagnosis of HIT is difficult in critically ill patients as both leading symptoms of HIT (thrombocytopenia and thrombosis) are not specific [21] . Although the absence of antiheparin/PF antibodies has a high negative predictive value to exclude HIT, it is not sufficient to detect these antibodies without further satisfying the stepwise criteria (Figure 1) including the 4Ts pretest clinical score [13,14] for the diagnosis of HIT [7,[9][10][11]15] . Our literature research revealed six studies, nine case reports, and six case series on anti-PF4/ heparin antibodies or HIT in solid organ transplant candidates and recipients.…”

Section: Assfalg V Et Al Hit In Solid Organ Transplant Recipientsmentioning

confidence: 99%

“…Overall, none of the liver transplant recipients developed HITTS in their systematic study. Furthermore, recipients who were clinically suspected to suffer from HIT according to 4Ts pretest clinical scoring system [7,[12][13][14] did not develop platelet activating antibodies in HIPA [61] .…”

Section: Liver Transplantationmentioning

confidence: 99%

“…In case of suspected HIT Ⅱ it is important to stop heparin application immediately, initiate laboratory investigations, and switch to a heparin-free anticoagulation regimen such as danaparoid, lepirudin, argatroban, or fondaparinux [12] . In daily clinical practice the 4Ts score (Table 1) has been repeatedly shown to serve as a reliable tool to assess the individual probability of HIT Ⅱ [7,[12][13][14] . A high 4T score together with a positive functional assay are regarded as being confirmatory for HIT.…”

Section: Introductionmentioning

confidence: 99%

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Heparin-induced thrombocytopenia in solid organ transplant recipients: The current scientific knowledge

Aßfalg

Hüser

2016

WJT

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Exposure to heparin is associated with a high incidence of immunization against platelet factor 4 (PF4)/heparin complexes. A subgroup of immunized patients is at risk of developing heparin-induced thrombocytopenia (HIT), an immune mediated prothrombotic adverse drug effect. Transplant recipients are frequently exposed to heparin either due to the underlying end-stage disease, which leads to listing and transplantation or during the transplant procedure and the perioperative period. To review the current scientific knowledge on antiheparin/PF4 antibodies and HIT in transplant recipients a systematic PubMed literature search on articles in English language was performed. The definition of HIT is inconsistent amongst the publications. Overall, six studies and 15 case reports have been published on HIT before or after heart, liver, kidney, and lung transplantation, respectively. The frequency of seroconversion for anti-PF4/heparin antibodies ranged between 1.9% and 57.9%. However, different methods to detect anti-PF4/heparin antibodies were applied. In none of the studies HIT-associated thromboembolic events or fatalities were observed. More importantly, in patients with a history of HIT, reexposure to heparin during transplantation was not associated with thrombotic complications. Taken together, the overall incidence of HIT after solid organ transplantation seems to be very low. However, according to the current knowledge, cardiac transplant recipients may have the highest risk to develop HIT. Different alternative suggestions for heparin-free anticoagulation have been reported for recipients with suspected HIT albeit no official recommendations on management have been published for this special collective so far. Core tip: Heparin-induced thrombocytopenia (HIT) Ⅱ is a life-threatening complication of heparin therapy. Transplant recipients frequently are exposed to high doses of heparin before, during, and after transplantation. This review gives a systematic overview MINIREVIEWS

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Assessment of the 4Ts Pretest Clinical Scoring System as a Predictor of Heparin‐Induced Thrombocytopenia

Cited by 30 publications

References 27 publications

Predictive value of the 4Ts scoring system for heparin-induced thrombocytopenia: a systematic review and meta-analysis

Predictive value of the 4Ts scoring system for heparin-induced thrombocytopenia: a systematic review and meta-analysis

Egyptian experience of reliability of 4T's score in diagnosis of heparin induced thrombocytopenia syndrome

Heparin-induced thrombocytopenia in solid organ transplant recipients: The current scientific knowledge

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