Lab Med Qual Assur.  2020 Dec;42(4):200-210. 10.15263/jlmqa.2020.42.4.200.

Analysis of Matrix Effect of Urine Quality Control Materials in Urine Chemistry Tests

• Jeon CH
• Kim SG

• KMID: 2510302
• DOI: http://doi.org/10.15263/jlmqa.2020.42.4.200

Abstract

Background
The National External Quality Assessment Service on urinalysis in Korea has used control materials manufactured by YD (YD Diagnostics, Korea). These materials are composed of phosphate-buffered saline mixed with real materials or chemical reagents. Therefore, matrix effects could influence the urine analysis results.
Methods
We obtained five kinds of control materials from YD Diagnostics, Aution Check Plus (Arkray Inc., Japan), Liquichek Urinalysis Control (BioRad Inc., USA), UroColor Control (Standard Diagnostics, Korea), and UCControl (Sysmex Co., Japan), and prepared normal and abnormal human urine samples for testing. As test devices, we selected the following six instruments: Super+ (YD Diagnostics), Aution Max AX-4030 (Arkray Inc.), UroMeter 720 Pro (Standard Diagnostics), Clinitek Adventus (Siemens Healthcare, Germany), URISYS 2400 (Roche Diagnostics, Germany), and UC1000 (Sysmex Co.) based on the database of the Korean Association of External Quality Assessment Service. We performed our analysis using the five control materials, two human urine samples, and six instruments.
Results
Matrix effects were found in all control materials: Aution Check (pH in URISYS, specific gravity [SG] in Aution Max), Liquichek (urobilinogen in Aution Max, SG in UC1000), UroColor (bilirubin and SG in Aution Max, pH and SG in UC1000), and UC-Control (bilirubin and SG in UroMeter, bilirubin in UC1000, and ketone in Clinitek). YD controls also presented matrix effects: blood and urobilinogen in Aution Max, glucose in Super+, SG in UC1000, and pH in URISYS.
Conclusions
Since all control materials showed matrix effects, external quality assessment should be evaluated by the results of the peer group rather than by those of the manufacturer.

Keyword

Urine; Quality control; Urinalysis