Interpretation of Ferritin Concentrations in the Dermatology Clinic.

Ferritin is a commonly measured laboratory test in dermatology. It is a marker of iron storage in the human body but also elevated in inflammatory states. Changes in ferritin are therefore non-specific and correlation of specific clinical findings and risk factors with ferritin concentration and other biomarkers e.g. iron studies or CRP are recommended. The article discusses iron metabolism and the indications for ferritin measurement in dermatology and how to interpret the results.

Pitfalls in the diagnosis and management of acid-base disorders in humans: a laboratory medicine perspective.

Diagnostic errors affect patient management, and as blood gas analysis is mainly performed without the laboratory, users must be aware of the potential pitfalls. The aim was to provide a summary of common issues users should be aware of.A narrative review was performed using online databases such as PubMed, Google Scholar and reference lists of identified papers. Language was limited to English.Errors can be pre-analytical, analytical or post-analytical. Samples should be analysed within 15 min and kept at room temperature and taken at least 15-30 min after changes to inspired oxygen and ventilator settings, for accurate oxygen measurement. Plastic syringes are more oxygen permeable if chilled. Currently, analysers run arterial, venous, capillary and intraosseous samples, but variations in reference intervals may not be appreciated or reported. Analytical issues can arise from interference secondary to drugs, such as spurious hyperchloraemia with salicylate and hyperlactataemia with ethylene glycol, or pathology, such as spurious hypoxaemia with leucocytosis and alkalosis in hypoalbuminaemia. Interpretation is complicated by result adjustment, for example, temperature (alpha-stat adjustment may overestimate partial pressure of carbon dioxide (pCO2) in hypothermia, for example), and inappropriate reference intervals, for example, in pregnancy bicarbonate, and pCO2 ranges should be lowered.Lack of appreciation for patient-specific and circumstance-specific reference intervals, including extremes of age and altitude, and transformation of measurements to standard conditions can lead to inappropriate assumptions. It is vitally important for users to optimise specimen collection, appreciate the analytical methods and understand when reference intervals are applicable to their specimen type, clinical question or patient.

Pitfalls in the Diagnosis and Management of Hypercortisolism (Cushing Syndrome) in Humans; A Review of the Laboratory Medicine Perspective.

Biochemical confirmation of a diagnosis of hypercortisolism (Cushing syndrome) is vital to direct further investigations, especially given the overlap with non-autonomous conditions, such as pseudo-Cushing, and the morbidity associated with missed diagnoses. A limited narrative review was performed focusing on the laboratory perspective of the pitfalls of making a biochemical diagnosis of hypercortisolism in those presenting with presumed Cushing syndrome. Although analytically less specific, immunoassays remain cheap, quick, and reliable in most situations. Understanding cortisol metabolism can help with patient preparation, specimen selection (e.g., consideration of urine or saliva for those with possible elevations of cortisol binding globulin concentration), and method selection (e.g., mass spectrometry if there is a high risk of abnormal metabolites). Although more specific methods may be less sensitive, this can be managed. The reduction in cost and increasing ease of use makes techniques such as urine steroid profiles and salivary cortisone of interest in future pathway development. In conclusion, the limitations of current assays, particularly if well understood, do not impede diagnosis in most cases. However, in complex or borderline cases, there are other techniques to consider to aid in the confirmation of hypercortisolism.

Bedbugs: how to diagnose and manage cases of infestations.

Bedbugs are on the rise in urban populations across the world, perhaps reflecting the ban on the use of organophosphates in many countries worldwide. They are flat obligate haematophagous insects, preferring humans, and as a consequence the bedbug bites lack toxins and can often go unnoticed for some time. Bites can, however, cause weals, purpura, petechiae, vesicles, pustules, papular urticaria, localized infection and rarely anaphylaxis. Infestations have to be confirmed by finding the bugs, usually around the bed of the person being bitten. Eradication usually requires a combination of physical (for example high temperature, mattresses protectors, traps, cold) and chemical methods (for example chrysanthemic acid derivatives plus potentiators such as geraniol and piperonyl butoxide or acetylcholine esterase inhibitors).

Real-world experience of SARS-CoV-2 antibody assays in UK healthcare workers.

BACKGROUND: The seroprevalence of antibodies to SARS-CoV-2 in healthcare workers is variable throughout the world. This study compares the use of two antibody assays among large cohorts of healthcare workers in southern England. METHODS: This cohort study includes data obtained from staff at Western Sussex Hospitals NHS Foundation Trust (WSHT) and Brighton and Sussex University Hospitals (BSUH) during voluntary antibody testing, using Abbott and Roche SARS-CoV-2 antibody assays at each Trust respectively. RESULTS: The observed seroprevalence level was 7.9% for the WSHT/Abbott cohort versus 13% for the BSUH/Roche cohort. Based on a previous positive PCR, we find that the false-negative rate of the Abbott and Roche assays were 60.2% and 19% respectively, implying sensitivity levels of 39.8% and 81%. Within these cohorts, seropositivity was most strongly associated with those of South Asian ethnicity, allied health professionals and male sex (p<0.0001). CONCLUSIONS: In this real-world study, neither antibody test performed to the specification level stated by the manufacturer. More rigorous testing of these and other assays in target populations is recommended prior to widespread usage if they are to provide data that might be useful to control the pandemic.