Based on the reduced exposure to posaconazole observed in the limited number of subjects in this study and the increased risk for adverse events associated with elevated rifabutin concentrations, concomitant use of rifabutin and posaconazole should be avoided unless the benefit outweighs the risk.

Venlafaxine is a phenethylamine derivative that has recently been approved for use in the treatment of depression. It is chemically unrelated to tricyclic, tetracyclic, or other available antidepressant agents. Anticholinergic, hypotensive, hypertensive, and cardiotoxic side effects are rare. Two fatal cases encountered at separate laboratories are discussed, both involve high levels of venlafaxine. Concentrations of the drug in peripheral blood, heart blood, urine, vitreous humor, and liver are reported. Descriptions of extraction and gas chromatographic methods for confirmation and quantitation are included.

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Introduction Specific patterns of blood test results are associated with COVID-19 infection. The aim of this study was to identify which blood tests could be used to assist in diagnosing COVID-19. Method A retrospective review was performed of consecutive patients referred to hospital with a clinical suspicion of COVID-19 over a period of 4 weeks. The patient’s clinical presentation, and SARS-CoV-2 RT-PCR (reverse-transcription polymerase chain reaction) were recorded. The patients were divided by diagnosis into COVID (COVID-19 infection) or CONTROL (an alternate diagnosis). A retrospective review of consecutive patients over a further 2-week period were used for the purposes of validation. Results Overall, 399 patients (53% COVID, 47% CONTROL) were analysed. White cell count (WCC), neutrophils (NEU) and lymphocytes (LYM) were significantly lower, while lactate dehydrogenase (LDH) and ferritin (FER) were significantly higher, in the COVID group in comparison to CONTROL. Combining the WCC, LYM and FER results into a COVID Combined Blood Test (CCBT) had an AUC of 0.79. Using a threshold CCBT of -0.8 resulted in a sensitivity of 0.85 and a specificity of 0.63. Analysing this against a further retrospective review of 181 suspected COVID-19 patients, using the same CCBT threshold, resulted in a sensitivity of 0.73 and a specificity of 0.75. The sensitivity was comparable to the SARS-CoV-2 RT PCR. Discussion Mathematically combining the blood tests has the potential to assist clinical acumen allowing for rapid streaming and more accurate patient flow pending definitive diagnosis. This may be of particular use in low resource settings.

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