From December 1997 to April 1998, 1060 laboratory-confirmed cryptosporidiosis cases were reported in New South Wales, Australia. In a case-control study, compared with 200 controls, the 100 cases were younger (mean age 42 versus 71 years; P < 0.0001), more likely to report swimming at a public pool (59% versus 38%; adjusted OR and 95% CI = 27; 1.4-5.1) and swimming in a dam, river or lake (OR = 48; 1.1-20.3) but less likely to report drinking bottled water (OR = 0.4; 0.2-0.9). In subgroup analyses, in rural areas illness was associated mainly with contact with another person with diarrhoea, and in urban areas illness was associated with swimming in a public pool. Cryptosporidium oocysts were more commonly detected in pools to which at least two notified cases had swum (P = 004). Outbreaks of cryptosporidiosis can be prolonged, involve multiple pools and be difficult to control.

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This eleventh best practice review examines two series of common primary care questions in laboratory medicine: (i) thyroid testing, and (ii) hypercalcaemia and hypocalcaemia. The review is presented in the same question–answer format as in the previous reviews. These questions and answers deal with common situations in men and non-pregnant women. The recommendations represent a précis of guidance found using a standardised literature search of national and international guidance notes, consensus statements, health policy documents and evidence-based medicine reviews, supplemented by Medline Embase searches to identify relevant primary research documents. In the case of the thyroid series, the recommendations are drawn from the 2006 guidelines published by the Association for Clinical Biochemistry, the British Thyroid Association and the British Thyroid Foundation. They are not standards but form a guide to be set in the clinical context. Most are consensus rather than evidence based. They will be updated periodically to take account of new information.