title: Diagnostic predictive value of platelet indices for discriminating hypo productive versus immune thrombocytopenia purpura in patients attending a tertiary care teaching hospital in Addis Ababa, Ethiopia.
abstract: BACKGROUND
  Bone marrow examination may be required to discriminate causes of thrombocytopenia as hypoproductive or hyperdestructive. However, this procedure is invasive and time consuming. This study assessed the diagnostic value of Mean Platelet Volume (MPV), Platelet Distribution Width (PDW) and Platelet Large Cell-Ratio (P-LCR) in discriminating causes of thrombocytopenia as hypoproductive or hyperdestructive (Immune thrombocytopenia purpura).
  
  
  METHODS
  A prospective cross-sectional study was conducted on 83 thrombocytopenic patients (Plt < 150 × 10(9)/L). From these, 50 patients had hypoproductive and the rest 33 Immune Thrombocytopenia Purpura (ITP). Age and sex matched 42 healthy controls were included as a comparative group. Hematological analysis was carried out using Sysmex XT 2000i 5 part diff analyzer. SPSS Version16 was used for data analysis. A two by two table and receiver operating characteristic (ROC) curve was used to calculate sensitivity, specificity, positive and negative predictive values, for a given platelet indices (MPV, PDW and P-LCR). Student t test and Mann Whitney U test were used to compare means and medians, respectively. Correlation test was used to determine associations between continuous variables.
  
  
  RESULTS
  All Platelet indices were significantly higher in ITP patients (n = 33) than in hypoproductive thrombocytopenic patients (n = 50) (p < 0.0001). In particular MPV and P-LCR have larger area under ROC curve (0.876 and 0.816, respectively), indicating a better predictive capacity, sensitivity and specificity in discriminating the two causes of thrombocytopenia. The indices were still significantly higher in ITP patients compared to 42 healthy controls (p < 0.0001). A significant negative correlation was observed between platelet count and platelet indices in ITP patients, (p < 0.001).
  
  
  CONCLUSIONS
  MPV, PDW and P-LCR help in predicting thrombocytopenic patients as having ITP or hypoproductive thrombocytopenia. If these indices are used in line with other laboratory and clinical information, they may help in delaying/ avoiding unnecessary bone marrow aspiration in ITP patients or supplement a request for bone morrow aspiration or biopsy in hypoproductive thrombocytopenic patients.
authors.affiliation: College of Health Science, Department of Medical Laboratory Science, Addis Ababa University, Addis Ababa, Ethiopia.
authors.forename: Mikias
authors.initials: M
authors.lastname: Negash
authors.affiliation: College of Health Science, Department of Medical Laboratory Science, Addis Ababa University, Addis Ababa, Ethiopia.
authors.forename: Aster
authors.initials: A
authors.lastname: Tsegaye
authors.affiliation: Department of Internal Medicine, Addis Ababa University, Addis Ababa, Ethiopia.
authors.forename: Amha
authors.initials: A
authors.lastname: G/Medhin
keywords: Bone marrow; Hypoproductive thrombocytopenia; Immune thrombocytopenia purpura (hyperdestructive thrombocytopenia); Platelet indices