Specimen preparation for microscopic analysis Specimen preparation Specimen preparation for microscopic analysis with a standardized method is highly recommended. Specimen of choice Acceptable delay between collection and processing. For routine urinalysis, the specimen of choice is the first-morning miction. This choice is a compromise.
Cytologists prefer the second-morning specimen but, the aim of the tests is quite different.
A free-voided specimen is often used, this being unavoidable for the emergency patient. The main disadvantage comes from the dilution of the specimen. This dilution, in some cases, can be sufficiently high to cause some false-negative results, especially with the chemistry testing. Delay between collection and processing. The ideal situation is when the specimen is analyzed shortly after miction.