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Thromboembolic conditions are a leading cause of mortality, estimated to account for 1 in 4 deaths worldwide in 2010. Over time, the incidence and mortality rates of these conditions have declined in developed countries, but are increasing in developing countries. A delicate balance exists between procoagulant and anticoagulant factors within the vascular system. Numerous acquired or inherited conditions may tip the balance either way, i.e. towards a prothrombotic or prohaemorrhagic state. Acquired thrombotic disorders are the subject of discussion in this issue, the second of a 2-part series on thrombophilia.

Background. The HIV epidemic in South Africa (SA) has had a substantial impact on laboratory services, at least partially owing to the well-described propensity to cytopenias in HIV-positive patients. Objectives. ( i ) To formally gauge the impact of HIV infection on the state sector haematology services in SA by determining the HIV seropositivity rate among full blood counts (FBCs) performed at a large academic state sector laboratory; and ( ii ) to document the prevalence of cytopenias among HIV-positive patients in this setting. Methods. Randomly selected FBCs submitted to the National Health Laboratory Service laboratory at Chris Hani Baragwanath Academic Hospital, Johannesburg, were extracted from the laboratory information system (LIS) and retrospectively reviewed. HIV test results and other pertinent information in the LIS were documented, as was the presence of any cytopenias. Results. HIV status was documented in 561 of 1 006 samples (55.8%), with 307 (54.7%) of these being HIV-positive. Of the HIV-positive patients, 63.2% had one or more cytopenia/s. Anaemia was present in 183/307 (59.6%) of the HIV-positive patients, and was severe (haemoglobin

Causes of thrombocytopenia range from laboratory errors to life-threatening pathological conditions. To establish the cause, appropriate laboratory investigation is required.To determine the prevalence and causes of platelet counts100 × 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.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 counts100 × 109/L were identified, and pertinent information was extracted from the laboratory database.Of 4 456 FBCs included, 381 (8.6%) had a platelet count of100 × 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 comprising20% 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 in5% 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.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.