title: Does routine repeat testing of critical laboratory values improve their accuracy?
abstract: BACKGROUND
  Routine repeat testing of critical laboratory values is very common these days to increase their accuracy and to avoid reporting false or infeasible results. We figure that repeat testing of critical laboratory values has any benefits or not.
  
  
  METHODS
  We examined 2233 repeated critical laboratory values in 13 different hematology and chemistry tests including: hemoglobin, white blood cell, platelet, international normalized ratio, partial thromboplastin time, glucose, potassium, sodium, phosphorus, magnesium, calcium, total bilirubin and direct bilirubin. The absolute difference and the percentage of change between the two tests for each critical value were calculated and then compared with the College of American Pathologists/Clinical Laboratory Improvement Amendments allowable error.
  
  
  RESULTS
  Repeat testing yielded results that were within the allowable error on 2213 of 2233 specimens (99.1%). There was only one outlier (0.2%) in the white blood cell test category, 9 (2.9%) in the platelet test category, 5 (4%) in the partial thromboplastin time test category, 5 (4.8%) in the international normalized ratio test category and none in other test categories.
  
  
  CONCLUSIONS
  Routine, repeat testing of critical hemoglobin, white blood cell, platelet, international normalized ratio, partial thromboplastin time, glucose, potassium, sodium, phosphorus, magnesium, calcium, total bilirubin and direct bilirubin results does not have any benefits to increase their accuracy.
authors.affiliation: General Practitioner, Iran University of Medical Sciences, Rasoul-e-Akram Hospital, Tehran, Iran. pooya_bmotie@yahoo.co.uk.
authors.forename: Pooya
authors.initials: P
authors.lastname: Baradaran Motie
authors.affiliation: Associate Professor, Iran University of Medical Sciences, Pathology Ward, Rasoul-e-Akram Hospital, Tehran, Iran. zaremir@gmail.com.
authors.forename: Ali
authors.initials: A
authors.lastname: Zare-Mirzaie
authors.affiliation: Associate Professor, Iran University of Medical Sciences, Pathology Ward, Rasoul-e-Akram Hospital, Tehran, Iran. nshayanfar@tums.ac.ir.
authors.forename: Nasrin
authors.initials: N
authors.lastname: Shayanfar
authors.affiliation: Professor, Iran University of Medical Sciences, Pathology Ward, Rasoul-e-Akram Hospital, Tehran, Iran. dmkadivar@gmail.com.
authors.forename: Maryam
authors.initials: M
authors.lastname: Kadivar
keywords: Accuracy; Allowable error; Critical values; Laboratory