Ann Lab Med.  2019 May;39(3):245-251. 10.3343/alm.2019.39.3.245.

Analytical and Clinical Performance of the Nanopia Krebs von den Lungen 6 Assay in Korean Patients With Interstitial Lung Diseases

• Cho EJ
• Park KJ
• Ko DH
• Koo HJ
• Lee SM
• Song JW
• Lee W
• Lee HK
• Do KH
• Chun S
• Min WK

• KMID: 2431601
• DOI: http://doi.org/10.3343/alm.2019.39.3.245

Abstract

BACKGROUND
Krebs von den Lungen 6 (KL-6) is a sensitive marker for diagnosing, monitoring, and predicting the prognoses of interstitial lung diseases (ILDs). This study aimed to evaluate the performance of the Nanopia KL-6 assay (Sekisui Medical, Tokyo, Japan) and to test the relationship between KL-6 concentrations and clinical results.
METHODS
In total, 230 patients diagnosed as having ILDs were enrolled. All underwent high-resolution computed tomography (HRCT) followed by the pulmonary function test (PFT). We also enrolled 116 disease controls and 200 healthy controls. Evaluation of the Nanopia KL-6 assay involved determination of precision, linearity, and limit of quantification (LOQ). Results from the Nanopia KL-6 assay were compared with those from ELISA and correlated with the HRCT and PFT results.
RESULTS
The within-laboratory precisions were < 2% of CV, and linearity was acceptable between 52.2 and 4,966.5 U/mL. The LOQ was 45.2 U/mL. Nanopia and ELISA results were strongly correlated (r=0.979). The average concentration of KL-6 was greater in ILD patients (711.5 U/mL) than in the disease (168.4 U/mL) and healthy (209.4 U/mL) controls. Serum KL-6 concentrations were strongly and moderately correlated with the extent of lung involvement and presence of typical HRCT abnormalities, respectively, and moderately correlated with PFT parameters.
CONCLUSIONS
The overall analytical and clinical performance of the Nanopia KL-6 assay was acceptable. Our study is the first to compare assay platforms and show correlations between KL-6 concentrations and HRCT or PFT results in Korean ILD patients.

Keyword

ELISA; High-resolution computed tomography; Interstitial lung diseases; Krebs von den Lungen 6; Performance evaluation; Pulmonary function test

MeSH Terms

Enzyme-Linked Immunosorbent Assay
Humans
Lung
Lung Diseases, Interstitial*
Prognosis
Respiratory Function Tests

Figure

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  Fig. 1 Linearity of the Nanopia Krebs von den Lungen 6 (KL-6) assay as estimated using the AU5822 analyzer (Beckman Coulter, Brea, CA, USA): the third-, second- and first-order models (A) and a difference plot (B) between the first- and third-order models at each concentration obtained from polynomial regression analysis.

• 

  Fig. 2 Scatter plots (A) and Bland-Altman bias plots (B) of the Krebs von den Lungen 6 (KL-6) concentrations of the automated Nanopia KL-6 assay and the manual KL-6 ELISA (N=50). In the scatter plot, the solid line is the Deming regression line, and dotted line is the 1:1 line. In the Bland-Altman plot, the solid line represents the average percent bias, dotted line is the zero line, and dashed lines are upper and lower 95% confidence limits for the mean difference (%). Percent bias was calculated using the following formula: (ELISA-Nanopia)/ELISA×100 (%).

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