Prevalence and causes of thrombocytopenia in an academic state sector laboratory in Soweto, Johannesburg, South Africa

Background: Causes of thrombocytopenia range from laboratory errors to life-threatening pathological conditions. To establish the cause, appropriate laboratory investigation is required.Objectives: To determine the prevalence and causes of platelet counts <100 × 109/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 × 109/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.Conclusion: 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

Evaluation of appendicitis risk prediction models in adults with suspected appendicitis

Background Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis. Methods A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis). Results Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent). Conclusion Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified