Light Microscopic Analysis of Urine - ZEISS Primo Star and ZEISS Axio Lab.A1

Oct 12, 2026

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Routine urinalysis supports medical laboratory screening for abnormalities in the physical and chemical composition of urine. The application note explains how urine is assessed visually, chemically with dipsticks, and microscopically after centrifugation of a sediment sample. It describes brightfield and phase-contrast examination to visualize cells, crystals, and pathogens, count findings, and report results. Examples illustrate erythrocytes, epithelial cells, bacteria, salts, and fungal elements. Brightfield/phase contrast microscopes like Primo Star and Axio Lab.A1 enhance visibility of transparent elements.

LanguageEnglish

CategoryGeneral

FormatPDF

Pages6

Reading Time2 min

AccessFree to download

Steps of Urinalysis

Visual analysis

Chemical analysis

Microscopic analysis

Application examples

Conclusion

Application Note Light Microscopic Analysis of Urine ZEISS Primo Star and ZEISS Axio Lab.A1 Light Microscopic Analysis of Urine ZEISS Primo Star and ZEISS Axio Lab.A1 | Author: | Carl Zeiss Microscopy GmbH, Germany | | --- | --- | | Date: | August 2015 | A microscopic examination is part of medical laboratory routine to analyze whether there are abnormalities in the physical or chemical examination of urine. Cells, crystals and other substances are reported and counted. An urinalysis of the urine sediment is typically performed in brightfield and phase contrast. It can reveal diseases such as diabetes mellitus, various forms of glomerulonephritis, and chronic urinary tract infections. Steps of Urinalysis a) Visual analysis Color, smell and appearance [Fig. 1] of fresh urine is first inspected visually. In general urine is yellow or amber in color and clear. Any turbidity or cloudiness may be caused by cellular material or protein in the urine or may develop from crystallization or precipitation of salts. Inserting a small amount of acid indicates that precipitation of salts is the probable cause of tubidity. An abnormal color could be sign of a special diet, a drug, or the presence of either hemoglobin or myoglobin. b) Chemical analysis The chemical examination of urine is mostly carried out using commercially prepared test strips the so called dipsticks. These are plastic strips that hold small squares of paper impregnated with chemicals. When the strip is dipped into urine, a chemical reaction changes the color of the paper squares . The color change is compared to a color chart provided with the test strips to determine the result for each test [Fig. 2] . The most frequently performed chemical tests using reagent test strips are: specific gravity, pH value, protein, glucose, ketones and blood. Figure 2: Chemical analysis of urine c) Microscopic analysis A microscopic analysis is typically performed to visualize blood cells, epithelial cells and pathogens, for example, when there are abnormal findings on the visual or chemical analysis. A sample of usually 10– 15 ml urine is centrifuged to concentrate the substances in it at the bottom of a tube [Fig. 3] . The fluid at the top of the tube is then discarded and the remaining sediment is examined under a microscope [Fig. 4 & 5] . Figure 3 Preparing the urine sample for the centrifuge Figure 4 Preparing the glass slide for light microscopic examination Urine sediment is normally examined with a transmitted light microscope with brightfield or phase contrast [Fig. 5] . Visualizing crystals’ polarization contrast can be helpful. The sediment is first examined with low magnification to identify most crystals, casts, squamous cells, and other large objects. Next, examination is carried out at high magnification to identify crystals, cells, and bacteria. All findings are counted and reported. Figure 5 Examination of urine with ZEISS Primo Star Application examples Figure 6 Erythrocytes (red blood cells) in urine showing thorn apple shape because of non-physiological pH-value of the urine Courtesy of: A. Michelsen, Clinic of Ortenau, Germany Figure 8 Squamous epithelial cells Courtesy of: A. Michelsen, Clinic of Ortenau, Germany Figure 10 Bacteria and Leukocytes. Bacteria are common in urine specimens. Courtesy of: G. Spengler-Schulz, Alexander Fleming School, Stuttgart, Germany Figure 7 Erythrocytes and leukocytes (white blood cells) in urine Courtesy of: G. Spengler-Schulz, Alexander Fleming School, Stuttgart, Germany Figure 9 Salts on a cylindrical structure Courtesy of: A. Michelsen, Clinic of Ortenau, Germany Figure 11 Fungus mycelium with yeast cells. Yeast cells may be contaminants or represent a true yeast infection. Courtesy of: A. Michelsen, Clinic of Ortenau, Germany Conclusion The urinalysis is used as a screening tool to detect substances or cellular material in the urine associated with different metabolic

FAQs

What is the goal of a urine microscopic analysis in routine labs?

It helps detect abnormalities by visualizing cells, crystals, and other substances in urine sediment and reporting counted findings associated with metabolic and kidney disorders.

How is the urine sediment prepared for microscopic examination?

A urine sample (typically 10–15 ml) is centrifuged to concentrate substances at the bottom of a tube, the supernatant is discarded, and the remaining sediment is examined on slides under a microscope.

Why are brightfield and phase-contrast microscopes recommended?

They allow clear visualization of transparent elements in urine, and the method supports identifying crystals, cells, and bacteria through low- and high-magnification steps.

Oct 12, 2026

Upload by Adam