Brightfield Information and Courses from MediaLab, Inc.
These are the MediaLab courses that cover Brightfield and links to relevant pages within the course.
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| Granular Casts Granular casts are composed of plasma protein aggregates and cellular remnants. Granular casts appear as cylinders of coarse, or fine, highly refractive particles. Coarsely granular casts (yellow arrow) contain large, coarse dark yellow or dark brown granules. They are very irregular in shape as shown in this high power magnification under the brightfield microscope. A hyaline cast can be seen just to the left of the coarse granular cast (blue arrow). | View Page |
| Fine Granular Casts Fine granular casts contain small refractive granules. These casts appear gray or pale yellow under the brightfield microscope. A phase contrast view is seen here.
The presence of an occasional granular cast is not considered pathologic. | View Page |
| Microscopic Examination of Urine Sediment The sediment may be examined using both brightfield and phase-contrast microscopy. With the brightfield microscope, subdued light must be used. Some structures will be missed if there is too much light in the field. Fine focus throughout the examination to identify structures in different focal planes.
Scan the slide on low power for quantification of casts, crystals and elements that are present in only a few fields. Use high power to identify casts and count red blood cells, white blood cells and epithelial cells. | View Page |
| Looking for Casts Scan the edges of the coverslip under low power (10x) phase contrast. The fine focus should be varied continuously while scanning. Count each type of cast seen under low power. Switch to high power brightfield to identify casts if needed. Determine the average of each type found and record the findings as number per low power field (#/LPF). | View Page |
| Counting Elements Next the number of RBCs, WBCs, epithelial cells, parasites, and fat will be counted. Move to the center of the coverslip and examine 10 fields under high power (40x) brightfield. Use phase-contrast as needed. Determine the average number of each element found and record the findings as number per high power field (#/HPF). An abundance of any one element may be recorded as >100/HPF when 1/4 field is counted and the total field is estimated to be greater than 200/HPF. | View Page |
| High Power of Enterobius vermicularis Ova On high power brightfield, the larva of Enterobius vermicularis can be seen within the thick hyaline shell. The egg measures 25 X 55 microns. | View Page |
| Oil or Fat Droplets Oil or fat droplets may appear as uniformly round bright globules of various sizes under high power brightfield. Oil droplets from catheter lubricants may be confused with cells, especially red cells. Lipid material from vaginal creams also forms droplets in urine. | View Page |