Some believe that the best doctors examine fresh urine sediment themselves during evaluation of sick patients and, thus, gain immediate information that can be clinically useful. Nephrologists examining urine sediment are more likely to identify clinically important findings as compared to laboratory technicians in some disease settings. In human medicine, the need for trained specialists to perform urine sediment examination as a biomarker for kidney disease continues to be emphasized, especially in patients with acute kidney injury ( AKI). In human medicine, the leukocyte esterase test pad is valuable to prompt microscopic sediment evaluation, but this reaction is not useful in veterinary medicine (see Chapter 5). Abnormal elements in urine sediment are more likely to be found during microscopy when urine has an abnormal color (colorless, very dark yellow, red, brown), if the urine is cloudy, if the USG is lower than normal, if USG is extremely high, or if the reagent pads on the dry reagent strip pad are positive for abnormalities (e.g. Macroscopic screening of urine based on its physical and chemical properties is sometimes used in human medicine to decide if urine sediment examination will be cost‐effective. Urine sediment examination has been referred to as the “liquid kidney biopsy”, but it also often reflects disorders of the lower urinary tract, so the moniker “liquid urinary tract biopsy” may be more apt. How the urine is mixed, what volume is centrifuged, the force of centrifugation, and the volume of sediment examined all should be standardized to obtain repeatable and accurate results. In veterinary medicine, standard manual urine microscopy has a within‐run coefficient of variation ( CV) of 30–40% for red blood cells ( RBC) and WBC. Failure to perform urine sediment microscopy can be attributed to the perception that it takes too much time (approximately 20 minutes to perform a complete urinalysis) and concern about the skill level and experience necessary for in‐clinic technicians to proficiently perform a urinalysis. White blood cells ( WBC), bacteria, fungal organisms, epithelial cells, crystals, and casts are not detected using dry‐reagent strip pad analysis. Unfortunately, urinary microscopy is often omitted in veterinary practice, which can result in failure to identify important diagnostic information. It is preferable to perform the complete urinalysis in‐house, though urine microscopy was considered optional by one veterinary author if the urinary chemistry reagent pads were all normal and there were no abnormalities in color or clarity of the urine specimen. Microscopic examination of the urine sediment should always be performed as part of the complete urinalysis, especially in animals that are sick and those that have abnormal color or clarity, abnormalities detected on chemical dipstrip testing (see Chapter 5), lower than expected urine specific gravity ( USG) ( Chapter 4), or on physical examination findings. Clinically important abnormalities have been observed by microscopy of urinary sediment in human medicine for over 400 years.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |