title: Prevalence and causes of thrombocytopenia in an academic state-sector laboratory in Soweto, Johannesburg, South Africa.
abstract: BACKGROUND
  Causes of thrombocytopenia range from laboratory errors to life-threatening pathological conditions. To establish the cause, appropriate laboratory investigation is required.
  
  
  OBJECTIVE
  To determine the prevalence and causes of platelet counts <100 × 10(9)/L in state health facilities in Johannesburg, South Africa, as well as the quality of the subsequent laboratory work-up in this setting.
  
  
  METHODS
  Full blood counts (FBCs) performed on 7 randomly selected days at the National Health Laboratory Service laboratory at Chris Hani Baragwanath Academic Hospital were retrospectively reviewed. Samples with platelet counts <100 × 109/L were identified, and pertinent information was extracted from the laboratory database.
  
  
  RESULTS
  Of 4 456 FBCs included, 381 (8.6%) had a platelet count of <100 × 10(9)/L. Thrombocytopenia prevalence rates were high in haematology/oncology wards (34.4%), intensive care units (20.5%) and medical wards (18.7%) and among neonatal inpatients (16.5%), and were lowest in outpatient clinics (1-2%). A cause was apparent in ~60% of patients, the commonest causes being chemotherapy and sepsis (each comprising >20% of the recognised causes). Spurious thrombocytopenia, disseminated tuberculosis, aplastic anaemia, immune thrombocytopenia and malignant marrow infiltration each accounted for 5 - 10% of the causes, while malaria, thrombotic thrombocytopenic purpura, HIV effect and liver disease were each identified in <5% of cases. HIV status was documented in ~70% of the patients, of whom ~50% tested positive. The quality of the laboratory work-up showed differences between specialties within the hospital setting, and was poorest in the primary healthcare clinic sector.
  
  
  CONCLUSIONS
  Thrombocytopenia is common in hospitalised patients in the Johannesburg academic state sector. Differences in the quality of the laboratory work-up emphasise the need for a standardised approach to thrombocytopenia investigation and increased awareness among clinicians.
authors: J L
authors: JL
authors: Vaughan
authors: J
authors: J
authors: Fourie
authors: S
authors: S
authors: Naidoo
authors: N
authors: N
authors: Subramony
authors: T
authors: T
authors: Wiggill
authors: N
authors: N
authors: Alli