= Solution
\b[<Urine microscopy> can identify the kind and possible site of urinary disease, directing further investigation and cause-specific treatment; a sediment finding alone is seldom a prescription.] This is a general methods question. No particular specimen, microscopic field or patient result is supplied.
Examine a fresh, properly collected sample, noting collection and storage conditions. After gentle mixing, examine a standardised sediment with a <microscope>: a low-power objective helps find <urinary casts>, while higher power characterises <cells>, <bacteria> and <crystals>. A <centrifuge> concentrates sediment when that method is used, but excessive delay or unsuitable processing can destroy <cells> and casts or generate crystals after collection. Interpret findings with symptoms, urine chemistry and kidney function; a dirty container or vaginal contamination can otherwise mimic urinary disease.<EFLM European Urinalysis Guideline (2023)>[urine particles, specimen stability and microscopy procedures]{ref}
<Red blood cells> indicate <haematuria>, whose source may be anywhere along the tract. <Red blood cell casts> or convincing dysmorphic <red blood cells> support a glomerular origin and justify assessment for <glomerulonephritis>, including renal function, <proteinuria> and appropriate referral. They do not establish a particular immunological cause. Isomorphic <red blood cells> with pain may suggest a stone; persistent unexplained <haematuria> also requires assessment for other urinary pathology. A historically tempting order to give an <astringent> would not address these different mechanisms.<Microhematuria guideline by AUA and SUFU (2025)>[initial evaluation, suspected medical renal disease and risk-based urinary evaluation]{ref}
Many <white blood cells>, with compatible symptoms and <bacteria>, support <urinary tract infection>; obtain a suitable <bacterial culture> when indicated and select an <antibiotic> according to the clinical syndrome and susceptibility. Contamination or asymptomatic bacteriuria is not equivalent to symptomatic <infection>. <White blood cell casts> favour an intrarenal process such as <pyelonephritis> or <interstitial nephritis>, so the treatment cannot be inferred from pus alone. Numerous squamous <epithelial cells> instead raise concern about collection quality.<Bacterial Urinary Tract Infections by Merck Manual>[urine testing, pyuria, bacteriuria and casts]{ref}
Renal tubular <epithelial cells> and granular casts can support <tubular injury>; fatty elements together with marked <proteinuria> suggest a nephrotic process. These findings direct assessment of kidney disease, fluid balance and potentially nephrotoxic exposures. A few hyaline casts may occur without a specific kidney disease. Casts are moulds formed within renal tubules; that origin is why they can localise a finding more effectively than free cells.<Urinary Casts by Merck Manual>[table, tubular, granular, fatty and hyaline casts]{ref}
<Urinary crystals> must be interpreted with urine acidity, concentration and the time after collection. <Uric acid> or <calcium oxalate> crystals can suggest a stone-forming environment but do not prove an obstructing stone or justify an unrestricted alkali prescription. Hexagonal <cystine> crystals raise a different metabolic question. Infection-associated phosphate stones require attention to the associated <infection> as well as stone management. Modern decisions combine stone analysis, imaging and metabolic assessment; hydration, urinary alkalinisation or other measures depend on the confirmed disorder. Microscopy does not by itself measure <glucose>, albumin loss or renal filtration, so these require separate tests.<EAU Guidelines on Urolithiasis>[metabolic evaluation and recurrence prevention: uric acid, cystine, calcium oxalate and infection stones]{ref}
Back to article page
