Q&A column

College of American Pathologists. COM.30840 Pipette carryover. In: All common checklist. Oct. 24, 2022.

Linda Whaley, MLS(ASCP)
Technical Specialist
Laboratory Accreditation Services
College of American Pathologists
Northfield, Ill.

Q. Our laboratory is assessing criteria for determining quantity not sufficient for a microscopic urinalysis. We were using an automated instrument but have gone back to manual microscopy for reasons beyond our control. While most textbooks state that 10 to 15 mL is the desired amount of sample for testing, it appears that many laboratories require smaller amounts. Can you provide guidance?

A.The exact volume required for a urine sample depends on the testing method used. A good rule of thumb is to require twice the volume required by an automated method to complete the chemical and microscopic portions of the urinalysis. This allows for sufficient volume to do a manual analysis or a repeat automated analysis should the initial automated analysis generate an instrument flag. So an automated instrument that requires 2 mL to complete one analysis would require a minimum volume of 4 mL.

For urine sample volumes of 2 to 4 mL, a laboratory’s policy could allow for a partial manual analysis, such as a manual dipstick with manual microscopic analysis. Urinalysis sample volumes of less than 2 mL typically are not analyzed, and they are reported as quantity not sufficient.

European Confederation of Laboratory Medicine. European urinalysis guidelines. Scand J Clin Lab Invest. 2000;60(suppl 231):1–96.

Timothy P. Skelton, MD, PhD
Medical Director
Core Laboratory and Laboratory Informatics
Lahey Hospital and Medical Center
Burlington, Mass.
Member, CAP Hematology/Clinical Microscopy Committee

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