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There is a wide variation in laboratory practice with regard to implementation and review of internal quality control (IQC). A poor approach can lead to a spectrum of scenarios from validation of incorrect patient results to over investigation of falsely rejected analytical runs. This article will provide a practical approach for the routine clinical biochemistry laboratory to introduce an efficient quality control system that will optimise error detection and reduce the rate of false rejection. Each stage of the IQC system is considered, from selection of IQC material to selection of IQC rules, and finally the appropriate action to follow when a rejection signal has been obtained. The main objective of IQC is to ensure day-to-day consistency of an analytical process and thus help to determine whether patient results are reliable enough to be released. The required quality and assay performance varies between analytes as does the definition of a clinically significant error. Unfortunately many laboratories currently decide what is clinically significant at the troubleshooting stage. Assay-specific IQC systems will reduce the number of inappropriate sample-run rejections compared with the blanket use of one IQC rule. In practice, only three or four different IQC rules are required for the whole of the routine biochemistry repertoire as assays are assigned into groups based on performance. The tools to categorise performance and assign IQC rules based on that performance are presented. Although significant investment of time and education is required prior to implementation, laboratories have shown that such systems achieve considerable reductions in cost and labour.

The term Munchausen syndrome is used to describe the patient who chronically fabricates or induces illness with the sole intention of assuming the patient role. Such persons often have a close association with the medical profession and thus use their knowledge to falsify symptoms and laboratory specimens to mimic disease. Cases of factitious disease have appeared in the literature originating from all medical specialties, and include such rare disorders as phaeochromocytoma and Bartter's syndrome. The laboratory can play a key role in the detection and diagnosis of factitious disorders. Indeed discrepant biochemistry results may provide the first clue to the diagnosis. Laboratory staff should be particularly aware of highly variable test results and extreme abnormalities that are not consistent with the wider biochemical profile, suggesting sample tampering. Factitious disorder should also be included in the clinician's differential diagnosis when disease presentation is unusual or an underlying cause cannot be found. Investigation to exclude or confirm factitious disorder at an early stage can prevent unnecessary testing in the search for increasingly rare diseases. Appropriate analyses may include screening tests for the detection of surreptitious drug administration or replication of a fabricated sample to confirm the method used. In all cases close communication between the clinician and laboratory is essential. This will ensure that appropriate tests are conducted particularly with regard to time critical and repeat tests.

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Aim To evaluate the blood gas and blood ketone abnormalities in children requiring intravenous fluids for management of gastroenteritis. Background Gastroenteritis commonly presents to acute paediatric services. Most children are successfully managed with oral rehydration therapy (ORT). However, some children will need intravenous (IV) fluids either due to failure of ORT or persistent vomiting. Ketones are produced by metabolising fat as an alternate energy source in place of carbohydrates. It is known that raised ketone levels in conditions like diabetic ketoacidosis can contribute to nausea and vomiting. Method There are two parts to this study. The first part is a retrospective observational study of children with gastroenteritis comparing 69 children requiring IV fluids to 87 children treated with ORT. The second part is a prospective study involving 32 children with gastroenteritis who required IV fluids. Blood sample was taken for blood gas and beta hydroxybutyrate (BOHB) levels while obtaining venous access. Treatment was carried out according to clinical requirements as per guidelines irrespective of the blood BOHB level. Results Both data sets had similar demographics of gender, age and weight centile. The retrospective data showed those on IV fluids compared to ORT were more acidotic (p < 0.001) with a raised anion gap (p = 0.0014). The observational data demonstrated that BOHB levels prior to IV fluid therapy were normal (<0.6) in 5 patients, mildly raised (0.6–1.5) in 5, moderately raised (1.6–3) in 7 and high (>3) in 15. Following a period of IV fluids there was a reduction in acidosis (p = 0.0034) and BOHB levels (p = 0.0026). Conclusion The majority of children with gastroenteritis who require IV fluids have a metabolic acidosis, raised anion gap and significantly raised BOHB levels. The study also illustrated a significant reduction in acidosis and BOHB with fluid management. Taking a blood gas and ketone level in children with vomiting as predominant symptom may aid in making an early decision about the need for IV fluid therapy. Using IV fluids may also ease nausea and vomiting by reducing the ketosis and acidosis in dehydrated children.