Evaluation of the Accuracy of Cr and BUN Using the ABL90 FLEX PLUS Blood Gas Analyzer and the Equivalence of Candidate Specimens for Assessment of Renal Function

Ha-Jin Lim; Seung-Yeob Lee; Hyun-Jung Choi

doi:10.3390/jcm12051940

Evaluation of the Accuracy of Cr and BUN Using the ABL90 FLEX PLUS Blood Gas Analyzer and the Equivalence of Candidate Specimens for Assessment of Renal Function

J Clin Med. 2023 Mar 1;12(5):1940. doi: 10.3390/jcm12051940.

Authors

Ha-Jin Lim¹, Seung-Yeob Lee^{2

3}, Hyun-Jung Choi¹

Affiliations

¹ Department of Laboratory Medicine, Chonnam National University Medical School and Hospital, Gwangju 61469, Republic of Korea.
² Department of Laboratory Medicine, Jeonbuk National University Medical School and Hospital, Jeonju 54907, Republic of Korea.
³ Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju 54907, Republic of Korea.

Abstract

Background: The ABL90 FLEX PLUS (Radiometer) is a blood gas analyzer that also provides creatinine (Cr) and blood urea nitrogen (BUN) results. We assessed the accuracy of the ABL90 FLEX PLUS to measure Cr and BUN and find suitable candidate specimens against primary specimens (heparinized whole-blood (H-WB)).

Methods: Paired H-WB, serum, and sodium-citrated whole-blood (C-WB) samples (105) were collected. The Cr and BUN levels in the H-WB using the ABL90 FLEX PLUS were compared with those of the serum using four automated chemistry analyzers. The suitability of the candidate specimens was assessed at each medical decision level according to the CLSI guideline EP35-ED1.

Results: The respective mean differences of the ABL90 FLEX PLUS for the Cr and BUN were below -0.10 and -3.51 mg/dL compared to the other analyzers. The systematic differences between the serum and the H-WB at the low, medium, and high medical decision levels were all 0% for Cr, but those of the C-WB were -12.96%, -11.81%, and -11.30%, respectively. Regarding imprecision, the SD_serum/SD_H-WB ratios at each level were 0.14, 1.41, and 0.68, whereas the SD_C-WB/SD_H-WB ratios were 0.35, 2.00, and 0.73, respectively.

Conclusions: The ABL90 FLEX PLUS provided Cr and BUN results comparable with the four widely used analyzers. Among the candidates, the serum was suitable for Cr testing using the ABL90 FLEX PLUS, while the C-WB did not satisfy the acceptance criteria.

Keywords: blood urea nitrogen; creatinine; kidney disease.

Grants and funding

This research received no external funding.