Comparison between a lipoprotein （a） particle concentration assay and 2 kinds of lipoprotein （a） mass concentration assays

doi:10.3969/j.issn.1673-8640.2017.07.004

Abstract

Abstract:

Objective To evaluate the performance of a new lipoprotein （a） [Lp （a）] particle concentration assay （method A） and 2 kinds of Lp（a） mass concentration assays（method B and method C）. Methods The precisions,linear ranges and clinical reportable ranges of the 3 methods were evaluated. The Lp（a） levels of 322 samples were determined by the 3 methods. Applying 75 nmol/L as the cut-off value for method A,and 300 mg/ L for method B and method C,the positive rates of the 3 methods in coronary artery disease （CAD）,peripheral artery disease （PAD）,cerebral stroke and healthy control groups were compared. Results The precisions,linear ranges and recovery rates of the 3 methods were acceptable. The clinical reportable ranges of the 3 methods were 0.8-920.0 nmol/ L,1-4 000 mg/L and 3-1 960 mg/L. Method B showed a good correlation with method A（R²=0.932）,while method C showed a poor correlation with method A（R²=0.631）. Compared to method A,Lp（a） levels were overestimated in 11.8% samples for method B and 13.7% samples for method C,and were underestimated in 3.1% samples for method C. Compared to healthy control group,Lp（a） levels of CAD,PAD and cerebral stroke groups all showed statistical significance（P<0.001）. The positive rate of method A in healthy control group was low,and there was no statistical significance for the positive rates of the 3 methods （P>0.05）. The positive rates of method B and method C in CAD and PAD groups were higher than those of method A （P<0.05）. The positive rate of method B in cerebral stroke group had no statistical significance with that of method A（P>0.05）,and that of method C was higher than that of method A （P<0.001）. Conclusions Method A for Lp （a） particle concentration can be traced to standard reference material（SRM）2B,and can reflect Lp（a） level correctly. Method B and method C for Lp（a） mass concentration overestimate Lp（a） levels compared with particle concentration. The levels of Lp（a） for predicting the risks of cardio vascular disease,PAD and cerebral stroke can be affected by the selection of methods and cut-off values.

Key words: Lipoprotein（a）, Coronary artery disease, Peripheral artery disease, Cerebral stroke, Methodology evaluation

CLC Number:

R446.1

JIA Keke, QIN Yanfei, YANG Shuo, ZHANG Jie. Comparison between a lipoprotein （a） particle concentration assay and 2 kinds of lipoprotein （a） mass concentration assays[J]. Laboratory Medicine, 2017, 32(7): 570-576.

Figures/Tables 6

References 17

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Lp（a）	批内		批间
Lp（a）	x±s （nmol/L）	CV （%）	x±s （nmol/L）	CV （%）
低值	18.85±0.82	4.35	18.66±0.92	4.88
中值	66.56±2.19	3.29	66.43±2.61	3.92
高值	138.57±3.09	2.23	138.29±3.00	2.17

Lp（a）	批内		批间
Lp（a）	x±s （nmol/L）	CV （%）	x±s （nmol/L）	CV （%）
低值	18.85±0.82	4.35	18.66±0.92	4.88
中值	66.56±2.19	3.29	66.43±2.61	3.92
高值	138.57±3.09	2.23	138.29±3.00	2.17

Lp（a）	批内		批间
Lp（a）	x±s （mg/L）	CV（%）	x±s （mg/L）	CV（%）
低值	70.13±2.63	3.75	70.30±2.74	3.90
中值	239.60±4.84	2.02	239.05±4.40	1.84
高值	480.5±9.61	2.00	480.85±7.43	1.54

Lp（a）	批内		批间
Lp（a）	x±s （mg/L）	CV（%）	x±s （mg/L）	CV（%）
低值	70.13±2.63	3.75	70.30±2.74	3.90
中值	239.60±4.84	2.02	239.05±4.40	1.84
高值	480.5±9.61	2.00	480.85±7.43	1.54

Lp（a）	批内		批间
Lp（a）	x±s （mg/L）	CV（%）	x±s （mg/L）	CV（%）
低值	167.84±4.75	2.83	167.74±6.55	3.91
中值	376.85±8.63	2.29	376.98±10.36	2.75
高值	518.23±9.38	1.81	517.61±11.28	2.18