Cardiol Res

Cardiology Research, ISSN 1923-2829 print, 1923-2837 online, Open Access

Article copyright, the authors; Journal compilation copyright, Cardiol Res and Elmer Press Inc

Journal website https://www.cardiologyres.org

Original Article

Volume 7, Number 2, April 2016, pages 51-58

Measuring B-Type Natriuretic Peptide From Capillary Blood or Venous Sample: Is It the Same?

Figures

Figure 1. Distribution of capillary BNP measured on the Alere Heart Check system according to plasma BNP measured on the Abbott Architect System among the 111 patients with CHF, examined in the study.

Figure 2. Bland-Altman comparison of capillary and plasma BNP.

Figure 3. In this ROC plot, there is the representation of the very good diagnostic performance (AUC = 0.983) of the Alere Check System as a tool for predicting a clinical picture of CHF belonging to NYHA classes II-IV. By adopting this method, the best diagnostic accuracy for identifying a condition of NYHA class II or higher has been attributed to the BNP threshold value of 412 pg/mL. This means that this value, when derived from a measurement made by the Alere Check System on capillary blood, is associated to the presence of heart failure symptoms with a sensitivity of 95.9% and a specificity of 91.9% (note on top of the graph). CHF: chronic heart failure; NYHA: New York Heart Association; ROC: receiver operating characteristic; AUC: area under the curve; BNP: B-type natriuretic peptide; pg: picogram.

Figure 4. In this ROC plot, there is the representation of the very good diagnostic performance (AUC = 0.984) of the Abbott Architect System as a tool for predicting a clinical picture of CHF belonging to NYHA classes II-IV. The criterion value of 438 pg/mL has been identified as the BNP value that exhibits the best diagnostic accuracy for predicting the presence of symptoms of heart failure. This means that this value, when the BNP measurement is done from plasma using the Abbott Architect System, is associated with heart failure symptoms with the best combination of sensitivity and specificity (91.8% and 96.8%, respectively). CHF: chronic heart failure; NYHA: New York Heart Association; ROC: receiver operating characteristic; AUC: area under the curve; BNP: B-type natriuretic peptide; pg: picogram.

Figure 5. Comparison of capillary (Alere Heart Check System) and plasma (Abbott Architect System) BNP levels in patients with chronic heart failure NYHA class I (no. 62 patient).

Figure 6. Comparison of capillary (Alere Heart Check System) and plasma (Abbott Architect System) BNP levels in chronic heart failure patients with NYHA class II (no. 30).

Figure 7. Comparison of capillary (Alere Heart Check System) and plasma (Abbott Architect System) BNP levels in chronic heart failure patients with NYHA class III (no. 19).

Tables

**Table 1.** Comparison of the Analytical Performance of POC* and Lab-Based** BNP Assays [6, 8, 9]
System	Sample type	CV low control	CV high control	Reference
CV: coefficient of variation; EDTA: ethylenediaminetetraacetic acid.
Abbott Architect**	EDTA plasma	5.5%	3.2%	[6]
Abbott i-STAT*	EDTA whole blood	14%	9.8%	[6]
Alere Heart Check*	Capillary whole blood	10.1% 8.4%	18% 14.1%	This study [8]
Alere Triage*	EDTA plasma	9.2%	11.4%	[9]

**Table 2.** NYHA Classification
NYHA class	Symptoms
I	Heart disease, but without resulting limitations of physical activity. Ordinary physical activity is not limited, but symptoms appear for activities out of the ordinary.
II	The patient is fine at rest but ordinary physical activity causes the appearance of symptoms.
III	Symptoms appear for even slight physical activities but the patient is fine at rest.
IV	The patient is unable to carry out any activity; he has symptoms even at rest.

**Table 3.** Characteristics of the Study Population (n = 111)
Characteristics
BMI: body mass index; NYHA: New York Heart Association; LVEF: left ventricular ejection fraction; CKD: chronic kidney disease; eGFR: estimated glomerular filtration rate; ICD: implantable cardioverter defibrillator; PM: pace-maker; BNP: B-type natriuretic peptide; ACE-I: angiotensin converting enzyme inhibitor; ARB: angiotensin receptor blocker.
Age	58 (47 - 65)
BMI	24.7 (21 - 29.2)
Men	72 (65%)
NYHA I	62 (55.8%)
NYHA II	30 (27%)
NYHA III	19 (17.1%)
LVEF (≤ 50%)	54 (48.6%)
LVEF (> 50%)	57 (51.3%)
Patient history
AF	34 (31%)
Moderate-to severe CKD (eGFR< 60 mL/min/m²)	47 (42%)
Hypertension	53 (48%)
Diabetes	24 (22%)
ICD/PM	17 (15%)
Etiology of heart failure
Ischemic	49 (44.1%)
Valvular	17 (15.3%)
Hypertensive	22 (19.9%)
Idiopathic	20 (18%)
Others	3 (2.7%)
Biology
eGFR (mL/min/m²)	67 (54 - 82)
Hematocrit (%)	42 (39 - 45)
Capillary BNP (pg/mL)	400 (245 - 678.75)
Plasma BNP (pg/mL)	399 (246.5 - 699)
Bilirubin (µmol/L)	13 (9 - 17)
Therapy
Beta-blocker	100 (90%)
Diuretics	82 (74%)
ACE-I/ARB	94 (85%)