A 59-year-old woman was admitted to intensive care after suffering a community cardiac arrest with ventricular fibrillation and 12 min downtime. She had a background of poorly controlled type 1 diabetes and severe chronic bilateral leg ulcers. A blood count showed hemoglobin concentration 85 g/L, mean cell volume 85.8 fL, red cell distribution width (RDW) 18.3% (normal range 10%–16%), and reticulocytes 117 × 10⁹/L; the platelet count and total and differential white cell counts were normal. A blood film showed anisopoikilocytosis, with elliptocytes, polychromasia, vacuolation of neutrophils, and reactive lymphocytes. A direct antiglobulin test was positive (2+) for immunoglobulin G. Lactate dehydrogenase was mildly increased, but bilirubin was normal. C-reactive protein was greatly increased at 197 mg/L. Microbiological cultures from the ulcers identified Staphylococcus aureus and Citrobacter koseri. These organisms were thought to have caused overwhelming sepsis leading to cardiac arrest.

A Perls stain for urinary hemosiderin was performed as part of investigation for suspected hemolysis. Unexpectedly, microscopy identified a partly filamentous microorganism with some budding yeast forms, which had been stained with the counterstain (images, ×100 objective). The presence of fungi was reported to clinical staff for further investigation and treatment.

Laboratories performing microscopy on blood, bone marrow, or urine should be alert to unexpected findings that may alter clinical management. Often this is the unanticipated presence of a microorganism—a bacterium, a fungus, or a parasite.

一名 59 岁的女性在社区心脏骤停伴有心室颤动和 12 分钟停机时间后被送往重症监护室。她有 1 型糖尿病控制不佳和严重的慢性双侧腿部溃疡的背景。血细胞计数显示血红蛋白浓度 85 g/L，平均细胞体积 85.8 fL，红细胞分布宽度 (RDW) 18.3%（正常范围 10%–16%），网织红细胞 117 × 10 ⁹/L; 血小板计数和白细胞总数及分类计数均正常。血涂片显示红细胞大小不等，伴有椭圆形红细胞、多染性、中性粒细胞空泡化和反应性淋巴细胞。直接抗球蛋白试验免疫球蛋白 G 呈阳性 (2+)。乳酸脱氢酶轻度升高，但胆红素正常。C-反应蛋白在 197 mg/L 时大大增加。溃疡的微生物培养鉴定出金黄色葡萄球菌和科氏柠檬酸杆菌。这些生物被认为导致了严重的败血症，导致心脏骤停。

作为疑似溶血调查的一部分，对尿含铁血黄素进行了 Perls 染色。出乎意料的是，显微镜发现了一种部分丝状微生物，具有一些发芽酵母形式，已用复染剂染色（图像，×100 物镜）。向临床工作人员报告了真菌的存在，以进行进一步调查和治疗。

对血液、骨髓或尿液进行显微镜检查的实验室应警惕可能改变临床管理的意外发现。这通常是微生物（细菌、真菌或寄生虫）的意外存在。