ORIGINAL ARTICLE Urine erythrocyte morphology in patients with microscopic haematuria caused by a glomerulopathy Giovanni Battista Fogazzi & Alberto Edefonti & Giuseppe Garigali & Marisa Giani & Anna Zolin & Sara Raimondi & Michael J. Mihatsch & Piergiorgio Messa Received: 13 September 2007 / Revised: 24 December 2007 / Accepted: 17 January 2008 / Published online: 7 March 2008 # IPNA 2008 Abstract The evaluation of urinary erythrocyte morpholo- gy (UEM) has been proposed for patients with isolated microscopic haematuria (IMH) to early orientate the diagnosis towards a glomerular or a nonglomerular disease. However, to date, the role of this test in patients with IMH has very rarely been investigated. Sixteen patients (ten children, six adults) with persistent IMH classified as glomerular on the basis of repeated UEM evaluations (55 urine samples, two to eight per patient) were submitted to renal biopsy. This showed a glomerular disease in 14/16 patients (87.5%) (nine thin basement membrane disease; three Alport syndrome; two other), whereas in two patients, no abnormalities were found. Of four microscopic criteria investigated to define a IMH as glomerular, >80% dysmorphic erythrocytes were not found in any sample, ≥40% dysmorphic erythrocytes alone were seen in seven samples (12.7%), ≥5% acanthocytes alone in 15 samples (27.3%) and erythrocytic casts in six samples (10.9%). There was ≥40% dysmorphic erythrocytes associated with ≥5% acanthocytes in 25 samples (45.5%). Sensitivity and positive predictive values in diagnosing a glomerular haematuria were 59.2% and 90.6%, respectively, for ≥40% dysmorphic erythrocytes, 69.4% and 85% for ≥5% acanthocytes/G1 cells and 12.2% and 100% for erythrocytic casts. Our findings demonstrate that the evaluation of UEM is useful to identify patients with an IMH of glomerular origin. Keywords Erythrocytic casts . Isolated microscopic haematuria . Urinary acanthocytes . Urinary dysmorphic erythrocytes . Urinary erythrocyte morphology . Urinary sediment examination Introduction Microscopic haematuria was described for the first time by François Rayer (1793–1867) and his associate Eugène Napoléon Vigla (1813–1872) in 1837 [1]. Today, the term isolated microscopic haematuria (IMH) applies to a condition characterised by “abnormal” numbers of erythrocytes in the urine. IMH is a rather common condition, affecting up 0.6– 4% of children [2, 3], 4–16% of adults [4, 5] and up to 20% of individuals over the age of 50 years [6, 7]. Due to the large variety of possible causes, the diagnostic workup may be complex, time consuming and expensive. In Pediatr Nephrol (2008) 23:1093–1100 DOI 10.1007/s00467-008-0777-2 G. B. Fogazzi (*) : G. Garigali : P. Messa Unità Operative di: Nefrologia–Laboratorio di ricerca sulle urine, Fondazione IRCCS, Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Via Commenda 15, 20122 Milano, Italy e-mail: fogazzi@policlinico.mi.it A. Edefonti : M. Giani Nefrologia ed Emodialisi Pediatrica, Fondazione IRCCS, Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Via Commenda 15, 20122 Milano, Italy A. Zolin Chirurgia Toracica, Fondazione IRCCS, Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Via Commenda 15, 20122 Milano, Italy S. Raimondi Divisione di Epidemiologia e Biostatistica, Istituto Europeo di Oncologia, Milano, Italy M. J. Mihatsch Institüt für Pathologie, Basel Universität, Basel, Switzerland