title: Evaluation of clinical and laboratory data for early diagnosis of heparin-induced thrombocytopenia.
abstract: OBJECTIVE
  Results of a study to determine the utility of combining laboratory values and clinical probability scores to improve the detection of heparin-induced thrombocytopenia (HIT) are reported.
  
  
  METHODS
  In a retrospective, single-site, chart review-based investigation, 156 cases in which patients with suspected HIT had positive results on a widely used diagnostic test (the anti-heparin/platelet factor 4, or anti-PF4, assay) were identified; in all cases, the blood specimens had been sent to a reference laboratory for confirmation of HIT via serotonin release assay (SRA). After investigator scoring of the clinical probability of HIT in each case by the 4T's method, a multiple logistic regression model was used to evaluate the combined effect of 4T's scores and anti-PF4 assay values in predicting SRA results.
  
  
  RESULTS
  4T's scores indicating an intermediate or high probability of HIT combined with high anti-PF4 test values (i.e., optical density [OD] value of ≥1.4) were strongly predictive of a positive SRA result, as were high-probability 4T's scores alone. Low-probability 4T's scores alone or in combination with anti-PF4 OD values of <1.4 were highly correlated with negative SRA results. Controlling for potential confounding factors, logistic regression analysis indicated that the 4T's score was a better predictor of SRA results than the anti-PF4 test value.
  
  
  CONCLUSIONS
  The combination of anti-PF4 OD values and 4T's scores accurately predicted SRA results, suggesting that the SRA may not be necessary to confirm HIT in patients with a relatively low 4T's score and a low anti-PF4 OD value.
authors.affiliation: Maryam Bayat, Pharm.D., BCPS (AQ-Cardiology), is Clinical Pharmacist II-Cardiology/Anticoagulation, Department of Pharmacy, Baylor St. Luke's Medical Center, Houston, TX. Francisco Yuri B. Macedo, M.D., Ph.D, is Cardiology Fellow, Department of Cardiology, Baylor Medical School, Houston. Ahmed S. Ansari, M.D., is Internal Medicine Resident, Internal Medicine Department, Baylor Medical School. Arthur W. Bracey, M.D., is Clinical Pathologist, Department of Pathology, Baylor St. Luke's Medical Center. Samuel Akinyele, Pharm.D., CPS, is Second-Year Pharmacy Resident-Cardiology; and Miguel Salazar, Ph.D., Pharm.D., BCPS, is Clinical Pharmacist-Oncology, Department of Pharmacy, Baylor St. Luke's Medical Center. mbayat@stlukeshealth.org.
authors.forename: Maryam
authors.initials: M
authors.lastname: Bayat
authors.affiliation: Maryam Bayat, Pharm.D., BCPS (AQ-Cardiology), is Clinical Pharmacist II-Cardiology/Anticoagulation, Department of Pharmacy, Baylor St. Luke's Medical Center, Houston, TX. Francisco Yuri B. Macedo, M.D., Ph.D, is Cardiology Fellow, Department of Cardiology, Baylor Medical School, Houston. Ahmed S. Ansari, M.D., is Internal Medicine Resident, Internal Medicine Department, Baylor Medical School. Arthur W. Bracey, M.D., is Clinical Pathologist, Department of Pathology, Baylor St. Luke's Medical Center. Samuel Akinyele, Pharm.D., CPS, is Second-Year Pharmacy Resident-Cardiology; and Miguel Salazar, Ph.D., Pharm.D., BCPS, is Clinical Pharmacist-Oncology, Department of Pharmacy, Baylor St. Luke's Medical Center.
authors.forename: Francisco Yuri B
authors.initials: FY
authors.lastname: Macedo
authors.affiliation: Maryam Bayat, Pharm.D., BCPS (AQ-Cardiology), is Clinical Pharmacist II-Cardiology/Anticoagulation, Department of Pharmacy, Baylor St. Luke's Medical Center, Houston, TX. Francisco Yuri B. Macedo, M.D., Ph.D, is Cardiology Fellow, Department of Cardiology, Baylor Medical School, Houston. Ahmed S. Ansari, M.D., is Internal Medicine Resident, Internal Medicine Department, Baylor Medical School. Arthur W. Bracey, M.D., is Clinical Pathologist, Department of Pathology, Baylor St. Luke's Medical Center. Samuel Akinyele, Pharm.D., CPS, is Second-Year Pharmacy Resident-Cardiology; and Miguel Salazar, Ph.D., Pharm.D., BCPS, is Clinical Pharmacist-Oncology, Department of Pharmacy, Baylor St. Luke's Medical Center.
authors.forename: Ahmed S
authors.initials: AS
authors.lastname: Ansari
authors.affiliation: Maryam Bayat, Pharm.D., BCPS (AQ-Cardiology), is Clinical Pharmacist II-Cardiology/Anticoagulation, Department of Pharmacy, Baylor St. Luke's Medical Center, Houston, TX. Francisco Yuri B. Macedo, M.D., Ph.D, is Cardiology Fellow, Department of Cardiology, Baylor Medical School, Houston. Ahmed S. Ansari, M.D., is Internal Medicine Resident, Internal Medicine Department, Baylor Medical School. Arthur W. Bracey, M.D., is Clinical Pathologist, Department of Pathology, Baylor St. Luke's Medical Center. Samuel Akinyele, Pharm.D., CPS, is Second-Year Pharmacy Resident-Cardiology; and Miguel Salazar, Ph.D., Pharm.D., BCPS, is Clinical Pharmacist-Oncology, Department of Pharmacy, Baylor St. Luke's Medical Center.
authors.forename: Arthur W
authors.initials: AW
authors.lastname: Bracey
authors.affiliation: Maryam Bayat, Pharm.D., BCPS (AQ-Cardiology), is Clinical Pharmacist II-Cardiology/Anticoagulation, Department of Pharmacy, Baylor St. Luke's Medical Center, Houston, TX. Francisco Yuri B. Macedo, M.D., Ph.D, is Cardiology Fellow, Department of Cardiology, Baylor Medical School, Houston. Ahmed S. Ansari, M.D., is Internal Medicine Resident, Internal Medicine Department, Baylor Medical School. Arthur W. Bracey, M.D., is Clinical Pathologist, Department of Pathology, Baylor St. Luke's Medical Center. Samuel Akinyele, Pharm.D., CPS, is Second-Year Pharmacy Resident-Cardiology; and Miguel Salazar, Ph.D., Pharm.D., BCPS, is Clinical Pharmacist-Oncology, Department of Pharmacy, Baylor St. Luke's Medical Center.
authors.forename: Samuel
authors.initials: S
authors.lastname: Akinyele
authors.affiliation: Maryam Bayat, Pharm.D., BCPS (AQ-Cardiology), is Clinical Pharmacist II-Cardiology/Anticoagulation, Department of Pharmacy, Baylor St. Luke's Medical Center, Houston, TX. Francisco Yuri B. Macedo, M.D., Ph.D, is Cardiology Fellow, Department of Cardiology, Baylor Medical School, Houston. Ahmed S. Ansari, M.D., is Internal Medicine Resident, Internal Medicine Department, Baylor Medical School. Arthur W. Bracey, M.D., is Clinical Pathologist, Department of Pathology, Baylor St. Luke's Medical Center. Samuel Akinyele, Pharm.D., CPS, is Second-Year Pharmacy Resident-Cardiology; and Miguel Salazar, Ph.D., Pharm.D., BCPS, is Clinical Pharmacist-Oncology, Department of Pharmacy, Baylor St. Luke's Medical Center.
authors.forename: Miguel
authors.initials: M
authors.lastname: Salazar
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D042241:Early Diagnosis; D005260:Female; D006403:Hematologic Tests / Q000379:methods*; D006493:Heparin / Q000009:adverse effects*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010978:Platelet Factor 4 / Q000378:metabolism; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D013921:Thrombocytopenia / Q000139:chemically induced* / Q000175:diagnosis*
chemical_list: D010978:Platelet Factor 4; D006493:Heparin