Quantitative analysis of total β-subunit of human chorionic gonadotropin concentration in urine by immunomagnetic reduction to assist in the diagnosis of ectopic pregnancy

Figures & data

Figure 1 Illustration of the association between hCGβ biomarkers and magnetic nanoparticles coated with anti-hCGβ antibodies.

Notes: (A) Magnetic nanoparticles oscillate and rotate individually with the applied external multiple ac magnetic fields before binding with hCGβ. (B) Magnetic nanoparticles become larger or clustered after binding with hCGβ, and thus oscillate and rotate much more slowly than the original individual magnetic nanoparticles.

Abbreviation: hCGβ, total β-subunit of human chorionic gonadotropin.

Figure 2 Illustration of magnetic nanoparticles.

Notes: (A) Magnetic iron oxide (Fe₃O₄) nanoparticles coated with dextran and anti-hCGβ antibodies. (B) Statistics of magnetic nanoparticle diameters with the mean of 52.8 nm.

Abbreviation: hCGβ, total β-subunit of human chorionic gonadotropin.

Figure 3 Immunomagnetic reduction assay of hCGβ.

Notes: (A) Real-time χ_ac signal of the magnetic reagent after being mixed with 1 ng/mL hCGβ solution. (B) IMR signals for independent duplicate tests of 1 ng/mL hCGβ solution.

Abbreviations: hCGβ, total β-subunit of human chorionic gonadotropin; IMR, immunomagnetic reduction.

Table 1 The mean value, SD, and CV of hCGβ concentration-dependent IMR signals for the standard calibration curve

ϕhCGβ (ng/mL)	Mean (%)	SD (%)	CV (%)
0.01	0.78	0.03	3.85
0.1	0.86	0.014	1.63
1	1.04	0.02	1.92
10	1.33	0.02	1.50
100	1.67	0.02	1.20
1,000	1.81	0.014	0.77
10,000	1.89	0.014	0.74

Abbreviations: hCGβ, total β-subunit of human chorionic gonadotropin; IMR, immunomagnetic reduction; SD, standard deviation; CV, coefficient of variation.

Figure 4 Calibration curve of IMR signals against hCGβ concentrations (R²=0.999).

Note: Points represent mean ± standard deviation.

Abbreviations: hCGβ, total β-subunit of human chorionic gonadotropin; IMR, immunomagnetic reduction.

Table 2 The mean value, SD, and CV of urine and serum hCGβ concentration-dependent IMR signals

Number	Sample type	Mean (%)	SD (%)	CV (%)
1	Urine	1.03	0.035	3.45
	Serum	0.94	0.028	3.01
2	Urine	2.23	0.028	1.27
	Serum	1.71	0.035	2.07
3	Urine	1.08	0.035	3.29
	Serum	0.96	0.028	2.95
4	Urine	2.38	0.049	2.08
	Serum	2.19	0.042	1.94
5	Urine	1.21	0.007	0.59
	Serum	1.14	0.028	2.48
6	Urine	1.13	0.028	2.5
	Serum	1.02	0.014	1.39
7	Urine	1.86	0.014	0.76
	Serum	1.7	0.014	0.83
8	Urine	1.24	0.021	1.72
	Serum	1.21	0.014	1.17
9	Urine	1.35	0.014	1.05
	Serum	1.13	0.014	1.25
10	Urine	1.58	0.042	2.69
	Serum	1.46	0.028	1.94

Abbreviations: hCGβ, total β-subunit of human chorionic gonadotropin; IMR, immunomagnetic reduction; SD, standard deviation; CV, coefficient of variation.

Figure 5 Relationship of total hCGβ IMR signals between urine and serum (R²=0.994).

Note: Points represent mean ± standard deviation.

Abbreviations: hCGβ, total β-subunit of human chorionic gonadotropin; IMR, immunomagnetic reduction.

Table 3 Comparison of urine hCGβ IMR signals and serum hCGβ CLIA values in the clinical samples

Number	IMR			CLIA (mIU/mL)	Detection week (week and day/7)	Final diagnosis
	Mean (%)	SD (%)	CV (%)
1	1.58	0.042	2.69	3,665	8 0/7	Ectopic pregnancy
2	1.43	0.014	0.99	2,867	5 6/7	Ectopic pregnancy
3	1.32	0.021	1.61	437.3	8 1/7	Abortion
4	1.2	0.014	1.18	185.1	5 3/7	Tubal abortion
5	1.86	0.014	0.76	9,353	5 5/7	Intrauterine pregnancy
6	1.35	0.014	1.05	477.3	6 4/7	Abortion
7	2.00	0.049	2.48	11,343	6 1/7	Intrauterine pregnancy
8	1.54	0.007	0.46	1,846	7 0/7	Ectopic pregnancy
9	1.59	0.007	0.45	2,291	4 6/7	Intrauterine pregnancy
10	1.49	0.007	0.48	3,292	6 4/7	Ectopic pregnancy
11	1.43	0.014	0.99	3,225	7 0/7	Ectopic pregnancy
12	1.68	0.021	1.27	3,992	5 3/7	Intrauterine pregnancy
13	1.53	0.042	2.77	3,018	8 6/7	Ectopic pregnancy
14	1.46	0.014	0.97	3,550	5 1/7	Intrauterine pregnancy
15	1.79	0.014	0.79	6,534	6 3/7	Ectopic pregnancy
16	1.96	0.049	2.53	7,552	4 4/7	Ectopic pregnancy
17	2.06	0.051	2.49	8,506	6 5/7	Ectopic pregnancy
18	1.65	0.021	1.29	4,512	6 5/7	Ectopic pregnancy
19	1.83	0.014	0.77	5,843	6 4/7	Ectopic pregnancy
20	1.87	0.007	0.38	7,021	4 6/7	Ectopic pregnancy

Abbreviations: hCGβ, total β-subunit of human chorionic gonadotropin; IMR, immunomagnetic reduction; CLIA, chemiluminescence immunoassay; SD, standard deviation; CV, coefficient of variation.

Figure 6 Relationship between urine hCGβ IMR signals and serum hCGβ CLIA values (R²=0.862).

Note: Points represent mean ± standard deviation.

Abbreviations: hCGβ, total β-subunit of human chorionic gonadotropin; IMR, immunomagnetic reduction; CLIA, chemiluminescence immunoassay.