Cancer Diagnosis Program | Biorepositories and Biospecimen Research Branch

Search BRD Papers

Preanalytics of urine sediment examination: effect of relative centrifugal force, tube type, volume of sample and supernatant removal.

Author(s): Bunjevac A, Gabaj NN, Miler M, Horvat A

Publication: Biochem Med (Zagreb), 2018, Vol. 28, Page 010707

PubMed ID: 29472802 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   This study investigated the effects of centrifugation protocol, tube shape, specimen volume, and supernatant removal method (decanting or suctioning) on the results of urine sediment analysis. Urine specimens from the nephrology and internal disease departments were delivered to the laboratory in urine collection cups. To investigate the effects of centrifugation protocol, 20 urine specimens were divided into two 10 mL round bottom no additive urine tubes and one was centrifuged at 400 x g for 5 min and the other at 1358 x g for 10 min. To investigate the effect of tube shape, 47 specimens were divided into a routine round-bottom tube and a conical-bottom Vacuette tube, centrifuged at 1358 x g for 10 min, and the supernatant was decanted. To investigate the effects of suctioning rather than decanting, 100 specimens were divided into two round-bottom tubes, centrifuged at 1358 x g for 10 min, and the supernatant was removed by decanting or suctioning with a disposable pipette. To evaluate the effects of specimen volume 101 specimens were aliquoted into 5 mL and 10 mL round-bottom tubes, centrifuged at 1358 x g for 10 min, and the supernatant was removed by decanting. All pellets were resuspended and a drop was evaluated by the same technician at 100X and 400X magnification.  Bacteria, mucus, and fungal counts were assigned a score of 0-3.

   Summary of Findings:

   Specimens centrifuged at 400 x g rather than 1358 x g had lower erythrocyte (1 versus 2, P=0.002), leukocyte (3 versus 9, P=0.001), and squamous epithelial cell (2 versus 6, P=0.004) counts, but all other parameters were unchanged. Specimens centrifuged in conical tubes had lower leukocyte counts than specimens in round-bottom tubes (3 versus 5, P=0.010). Removal of the supernatant by suction rather than decanting resulted in lower leukocyte counts (4 versus 5, P=0.045) and fewer squamous epithelial cells (3 versus 3, P<0.001). Use of a 5 mL tube rather than a 10 mL tube resulted in lower erythrocyte (2 versus 4, P<0.001), leukocyte (5 versus 3, P<0.001), and squamous epithelial cell (2 versus 3, P<0.001) counts and fewer non-hyaline (0 versus 0, P<0.001) and granular (34 versus 48, P=0.039) casts. The number of leukocytes in clusters, small squamous cells, hyaline casts, bacteria, mucus, and fungi were unaffected by centrifugation protocol, tube shape, specimen volume, or method of supernatant removal.

   Biospecimens

   • Bodily Fluid - Urine

   Preservative Types

   • None (Fresh)

   Diagnoses:

   • Not specified

   Platform:

   Analyte	Technology Platform
   Cell count/volume	Light microscopy

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Biospecimen Aliquots and Components	Aliquot size/volume	5 mL 10 mL
   Biospecimen Aliquots and Components	Centrifugation	Multiple durations compared Multiple speeds compared
   Biospecimen Acquisition	Type of collection container/solution	Conical tube Round bottom tube
   Biospecimen Aliquots and Components	Blood processing method	Supernatant removal by decanting Supernatant removal by suctioning

   View more