- Email: [email protected]
Human heart-type fatty acid-binding protein for on-site diagnosis of early acute myocardial infarction
420
Letters to the Editor
Human heart-type fatty acid-binding protein for on-site diagnosis of early acute myocardial infarction Jun Liao a,⁎, Cangel Pui-yee Chan b , Yiu-chi Cheung b , Jian-hua Lu c , Yi Luo c , George W.H. Cautherley d , Jan F.C. Glatz e , Reinhard Renneberg b,⁎ a
Department of Laboratory Science, First Municipal People's Hospital of Guangzhou, Affiliated of Guangzhou Medical College, 510180, Guangzhou, PR China b Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong c Department of Emergency, First Municipal People's Hospital of Guangzhou, Affiliated of Guangzhou Medical College, Guangzhou, PR China d R&C Biogenius Limited, Hong Kong e Department of Molecular Genetics, Cardiovascular Research Institute Maastricht, Maastricht University, The Netherlands Received 25 November 2007; accepted 20 January 2008 Available online 20 June 2008
Abstract Human heart-type fatty acid-binding protein (H-FABP) has a high potential as an early marker for acute myocardial infarction (AMI) being more sensitive than current routine cardiac markers. Seventy-four patients presenting to hospital with a median symptom onset of 2.2 h (IQR 1.5–2.9 h) were enrolled in this study and 54 (73%) had AMI. At presentation, H-FABP gave the highest sensitivity of 83.3% (95% CI: 70.7–92.1) and troponin I (cTnI) gave the highest specificity of 50.0% (95% CI: 27.2–72.8). This study demonstrated that H-FABP immunotest gave a better diagnostic classification at the early stage. Also, AMI was identified significantly earlier by H-FABP than cTnI (17 vs. 6 patients, p b 0.05). © 2008 Elsevier Ireland Ltd. All rights reserved. Keywords: Acute myocardial infarction; Cardiac troponin I; Creatine kinase MB; Heart-type fatty acid-binding protein; Myoglobin
1. Introduction Heart-type fatty acid-binding protein (H-FABP), a low molecular mass cytoplasmic protein (15 kD) abundant in heart muscle cells, has a high potential as a sensitive biomarker for early diagnosis of AMI [1–3]. H-FABP levels rise as early as 1–3 h after the onset of AMI, peak at 6–8 h, and return to normal within 24–30 h. A one-step H-FABP immunotest so-called CardioDetect® designed to detect H-FABP in whole blood samples is now commercially available [4–6]. The test result is available within 15 min after addition of blood samples. It requires no sample pretreatment and thus can be applied in emergency situation. Combined with the well-established markers, troponins, it may allow more accurate targeting of appropriate therapy and considerable cost savings than the current diagnostic tests.
⁎ Corresponding authors. Renneberg is to be contacted at Fax: 852-2358 7387. Liao, Fax: 86-020-8104 8011. E-mail addresses: [email protected] (J. Liao), [email protected] (R. Renneberg).
The aim of the present study was to evaluate the diagnostic performance of the H-FABP immunotest in patients suspected with myocardial infarction compared to myoglobin, CK-MB and cardiac troponin I (cTnI). 2. Methods 2.1. Participants The study took place at the Emergency Department (ED) of the Guangzhou First Municipal People's Hospital in Guangzhou, China. Patients presenting to the ED were consecutively screened for entry criteria: onset of acute chest pain and/or dyspnoea lasting for at least 20 min within the last 3 h, age N 18 years. A total of 100 patients met these entry criteria, of whom 74 were included; the reasons for exclusion are listed in Fig. 1. 2.2. H-FABP immunotest A rapid chromatographic immunoassay designed for qualitative determination of H-FABP in blood samples was
Letters to the Editor
421
Fig. 1. Flow chart of study population.
performed with a cut-off level of 7 µg/L (CardioDetect®, rennesens GmbH). The test required 100–120 µL of sample and the result was interpreted within 15 min after sample application. Tests were judged to be positive or negative; invalid tests without control lines were repeated immediately.
specificity, negative and positive predictive values, and likelihood ratios were calculated by using MedCalc, version 7.0 (MedCalc Software, Mariakerke, Belgium). McNemar test was used to assess whether H-FABP or cTnI was positive earlier. The level of significance was set at p b 0.05. 3. Results and discussion
2.3. Statistics Data are presented as medians, interquartile ranges (IQR), means ± standard deviation (SD) or 95% confidence intervals (95% CI). Diagnostic test criteria including sensitivity,
Between 25 October 2006 and 3 April 2007, a total of 74 patients were enrolled out of 100 patients meeting the entry criteria (Fig. 1). Mean age was 69.0 ± 12.4 years (range: 40–90 years), and 54 (73%) were male. Median time
Table 1 Diagnostic test characteristics of H-FABP at hospital presentation.
Overall Age ≥55 years b55 years Sex Female Male Hypertension Yes No Diabetes Yes No CRF Yes No Death Yes No
n
AMI prevalence
Sensitivity
Specificity
LR (+)
LR (−)
PPV
NPV
74
54 (73%)
83.3 (70.7–92.1)
30.0 (12.0–54.3)
1.19
0.56
76.3
40.0
62 12
45 (73%) 9 (75%)
80.0 (65.4–90.4) 55.6 (21.4–86.0)
47.1 (23.0–72.1) 66.7 (11.6–94.5)
1.51 1.67
0.42 0.67
80 83.3
47.1 33.3
20 54
16 (80%) 38 (70%)
81.3 (54.3–95.7) 73.7 (56.9–86.6)
25.0 (4.1–79.7) 56.3 (29.9–80.2)
1.08 1.68
0.75 0.47
81.2 80
25.0 47.4
34 40
28 (28%) 26 (65%)
89.3 (71.7–97.6) 61.5 (40.6–79.7)
50.0 (12.4–87.6) 50.0 (23.1–76.9)
1.79 1.23
0.21 0.77
89.3 69.6
50.0 41.2
14 60
12 (86%) 42 (70%)
75.0 (42.8–94.2) 76.2 (60.5–87.9)
50.0 (8.2–91.8) 50.0 (26.1–73.9)
1.50 1.52
0.50 0.48
90.0 78.0
25.0 47.4
4 70
0 (0%) 54 (77%)
– 75.9 (62.4–86.5)
– 56.3 (29.9–80.2)
– 1.74
– 0.43
– 85.4
– 40.9
6 68
5 (83%) 49 (72%)
80.0 (51.9–95.4) 75.5 (61.1–86.6)
0.0 52.6 (28.9–75.5)
0.80 1.59
– 0.47
80.0 80.4
0.0 45.5
Data are numbers, percentages, or mean (95% CI), as appropriate. AMI: Acute myocardial infarction; LR: likelihood ratio; PPV: positive predictive value; NPV: negative predictive value; CRF: chronic renal failure.
422
Letters to the Editor
Table 2 Sensitivities, specificities, likelihood values and predictive values of different cardiac markers for diagnosis of AMI.
FABP Myoglobin cTnI CK-MB
Cut-off (µg/L)
Sensitivity
Specificity
LR (+)
LR (−)
PPV
NPV
7.0 70 0.5 4.0
83.3 (70.7–92.1) 75.9 (62.4–86.5) 64.8 (50.6–77.3) 65.0 (40.8–84.5)
30.0 (12.0–54.3) 25.0 (8.8–49.1) 50.0 (27.2–72.8) 35.2 (22.7–49.4)
1.19 1.01 1.30 1.00
0.56 0.96 0.70 0.99
76.3 73.2 77.8 72.9
40.0 27.8 34.5 26.9
Data are numbers, or mean (95% CI), as appropriate. FABP: Fatty acid-binding protein; cTnI: cardiac troponin I; CK-MB: creatine kinase MB; LR: likelihood ratio; PPV: positive predictive value; NPV: negative predictive value.
from symptom onset to first blood sample was 2.2 h (IQR 1.5–2.9 h). Thirty-four patients (46%) had hypertension, 14 (19%) had diabetes, 4 (5.4%) had chronic renal failure (CRF), and 6 (8.1%) died during their hospital stay. Acute myocardial infarction was diagnosed in 54 (73%) individuals, of whom 39 (53%) had STEMI and 15 (20%) had NSTEMI. The non-AMI group consisted of 20 patients with a final diagnosis of hypertension, stable angina, pneumonia, paroxysmal ventricular tachycardia, femoral artery infarction and chronic renal failure. 3.1. Diagnostic performance of H-FABP immunotest Table 1 shows the diagnostic performance of H-FABP at presentation. The sensitivity and specificity of H-FABP at presentation were 83.3% and 30.0% respectively. Better test performance was found in elderly patients, females and patients with hypertension. Compared to younger patients, sensitivity was higher in older patients, but the inverse was observed for specificity. Females had higher sensitivity but lower specificity than males. Patients with diabetes did not affect the diagnostic performance.
The myocardial content of H-FABP (0.57 mg/g wet weight) is four- to five-fold lower than that of myoglobin (2.7 mg/g wet weight), yet the plasma reference concentration of H-FABP (1.8 µg/L) is 19-fold lower than that of myoglobin (34 µg/L). This means that after injury the tissue to plasma gradient is almost five-fold steeper for H-FABP than for myoglobin, making plasma H-FABP rise above its upper reference concentration at an earlier point after AMI onset, thus permitting an earlier diagnosis of AMI [1,7]. 3.4. Receiver operator characteristic curves for different cardiac markers The areas under the receiver operator characteristic (ROC) curves to distinguish AMI from non-AMI within 3 h after the onset of symptoms were 0.639 (95% CI: 0.490– 0.787) for H-FABP, 0.574 (95% CI: 0.425–0.723) for myoglobin, 0.499 (0.350–0.648) for CK-MB, and 0.505 (95% CI: 0.355–0.654) for cTnI. The area under the curve for H-FABP was significantly greater than those of the other cardiac markers within 3 h after the onset of symptoms. Thus, H-FABP has great potential as an excellent cardiac marker for diagnosis of AMI in the early phase.
3.2. Comparison of H-FABP and cTnI 4. Conclusion Of the 53 patients in whom both H-FABP and cTnI were positive, H-FABP was positive earlier than cTnI in 17 patients, whereas cTnI was positive earlier than H-FABP in 6 (p b 0.05). In this study, we demonstrated that H-FABP was positive significantly earlier than cTnI. All the patients presented to hospital within 3 h after symptom onset, when H-FABP might already be detectable, but not cTnI. Nonetheless, cTnI was elevated earlier in 11% of AMI patients. Variability in reporting of time delay after symptom onset may contribute to this finding.
In this study, we aimed to evaluate the accuracy of HFABP in a point-of-care setting for early diagnosis of myocardial damage in patients presenting to the ED suspected of AMI. H-FABP could not by itself diagnose AMI with adequately high accuracy, but when positive, it was usually faster than cTnI. In order to decrease the risk of falsely excluded patients with ongoing AMI, a combined measurement of two biochemical markers, an early one such as HFABP and a later marker such as troponins may provide the optimum diagnostic performance.
3.3. Sensitivities and specificities for different cardiac markers
Acknowledgements
The sensitivities and specificities of different cardiac markers are listed in Table 2. H-FABP gave the highest sensitivity (83.3%) for early exclusion of non-AMI patients, whereas cTnI gave the highest specificity (50.0%) for inclusion of AMI patients. H-FABP also had a higher sensitivity and specificity (30.0%) than myoglobin (sensitivity: 75.9%; specificity: 25.0%).
We thank the staff of the Emergency Department and the Department of Laboratory Medicine of Guangzhou First Municipal People's Hospital for their dedication and for diligently ensuring the highest possible level of data capture. We also thank Shenzhen Kang Sheng Bao Bio-Technology Co. Ltd. (Shenzhen, China) for donation of H-FABP immunotests (CardioDetect®).
Letters to the Editor
References [1] Glatz JFC, Van der Voort D, Hermens WT. Fatty acid-binding protein as the earliest available plasma marker of acute myocardial injury. J Clin Ligand Assay 2002;25:167–77. [2] Nakata T, Hashimoto A, Hase M, Tsuchihashi K, Shimamoto K. Human heart-type fatty acid-binding protein as an early diagnostic and prognostic marker in acute coronary syndrome. Cardiology 2003;99:96–104. [3] Chan CP, Sanderson JE, Glatz JFC, Cheng WS, Hempel A, Renneberg R. A superior early myocardial infarction marker. Human heart-type fatty acid-binding protein. Z Kardiol 2004;93:388–97. [4] Chan CP , Lehmann M, Renneberg I, et al. A Novel Credit-Card Style Assay for Beside Determination of Fatty Acid-Binding Protein. IVD Technology Magazine 2006;12:51.
0167-5273/$ - see front matter © 2008 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijcard.2008.01.049
423
[5] Chan CP, Cheng WS, Glatz JFC, et al. Early diagnosis of acute myocardial infraction using immunosensors and immunotests. J Anal Lett 2003;36:1987–2004. [6] Chan CP, Sum KW, Cheung KY, et al. Development of a quantitative lateral-flow assay for rapid detection of fatty acid-binding protein. J Immunol Methods 2003;279:91–100. [7] Glatz JFC, Kleine AH, Van Nieuwenhoven FA, Hermens WT, Van Dieijen-Visser MP, Van der Vusse GJ. Fatty-acid-binding protein as a plasma marker for the estimation of myocardial infarct size in humans. Br Heart J 1994;71:135–40.
Letters to the Editor
Human heart-type fatty acid-binding protein for on-site diagnosis of early acute myocardial infarction Jun Liao a,⁎, Cangel Pui-yee Chan b , Yiu-chi Cheung b , Jian-hua Lu c , Yi Luo c , George W.H. Cautherley d , Jan F.C. Glatz e , Reinhard Renneberg b,⁎ a
Department of Laboratory Science, First Municipal People's Hospital of Guangzhou, Affiliated of Guangzhou Medical College, 510180, Guangzhou, PR China b Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong c Department of Emergency, First Municipal People's Hospital of Guangzhou, Affiliated of Guangzhou Medical College, Guangzhou, PR China d R&C Biogenius Limited, Hong Kong e Department of Molecular Genetics, Cardiovascular Research Institute Maastricht, Maastricht University, The Netherlands Received 25 November 2007; accepted 20 January 2008 Available online 20 June 2008
Abstract Human heart-type fatty acid-binding protein (H-FABP) has a high potential as an early marker for acute myocardial infarction (AMI) being more sensitive than current routine cardiac markers. Seventy-four patients presenting to hospital with a median symptom onset of 2.2 h (IQR 1.5–2.9 h) were enrolled in this study and 54 (73%) had AMI. At presentation, H-FABP gave the highest sensitivity of 83.3% (95% CI: 70.7–92.1) and troponin I (cTnI) gave the highest specificity of 50.0% (95% CI: 27.2–72.8). This study demonstrated that H-FABP immunotest gave a better diagnostic classification at the early stage. Also, AMI was identified significantly earlier by H-FABP than cTnI (17 vs. 6 patients, p b 0.05). © 2008 Elsevier Ireland Ltd. All rights reserved. Keywords: Acute myocardial infarction; Cardiac troponin I; Creatine kinase MB; Heart-type fatty acid-binding protein; Myoglobin
1. Introduction Heart-type fatty acid-binding protein (H-FABP), a low molecular mass cytoplasmic protein (15 kD) abundant in heart muscle cells, has a high potential as a sensitive biomarker for early diagnosis of AMI [1–3]. H-FABP levels rise as early as 1–3 h after the onset of AMI, peak at 6–8 h, and return to normal within 24–30 h. A one-step H-FABP immunotest so-called CardioDetect® designed to detect H-FABP in whole blood samples is now commercially available [4–6]. The test result is available within 15 min after addition of blood samples. It requires no sample pretreatment and thus can be applied in emergency situation. Combined with the well-established markers, troponins, it may allow more accurate targeting of appropriate therapy and considerable cost savings than the current diagnostic tests.
⁎ Corresponding authors. Renneberg is to be contacted at Fax: 852-2358 7387. Liao, Fax: 86-020-8104 8011. E-mail addresses: [email protected] (J. Liao), [email protected] (R. Renneberg).
The aim of the present study was to evaluate the diagnostic performance of the H-FABP immunotest in patients suspected with myocardial infarction compared to myoglobin, CK-MB and cardiac troponin I (cTnI). 2. Methods 2.1. Participants The study took place at the Emergency Department (ED) of the Guangzhou First Municipal People's Hospital in Guangzhou, China. Patients presenting to the ED were consecutively screened for entry criteria: onset of acute chest pain and/or dyspnoea lasting for at least 20 min within the last 3 h, age N 18 years. A total of 100 patients met these entry criteria, of whom 74 were included; the reasons for exclusion are listed in Fig. 1. 2.2. H-FABP immunotest A rapid chromatographic immunoassay designed for qualitative determination of H-FABP in blood samples was
Letters to the Editor
421
Fig. 1. Flow chart of study population.
performed with a cut-off level of 7 µg/L (CardioDetect®, rennesens GmbH). The test required 100–120 µL of sample and the result was interpreted within 15 min after sample application. Tests were judged to be positive or negative; invalid tests without control lines were repeated immediately.
specificity, negative and positive predictive values, and likelihood ratios were calculated by using MedCalc, version 7.0 (MedCalc Software, Mariakerke, Belgium). McNemar test was used to assess whether H-FABP or cTnI was positive earlier. The level of significance was set at p b 0.05. 3. Results and discussion
2.3. Statistics Data are presented as medians, interquartile ranges (IQR), means ± standard deviation (SD) or 95% confidence intervals (95% CI). Diagnostic test criteria including sensitivity,
Between 25 October 2006 and 3 April 2007, a total of 74 patients were enrolled out of 100 patients meeting the entry criteria (Fig. 1). Mean age was 69.0 ± 12.4 years (range: 40–90 years), and 54 (73%) were male. Median time
Table 1 Diagnostic test characteristics of H-FABP at hospital presentation.
Overall Age ≥55 years b55 years Sex Female Male Hypertension Yes No Diabetes Yes No CRF Yes No Death Yes No
n
AMI prevalence
Sensitivity
Specificity
LR (+)
LR (−)
PPV
NPV
74
54 (73%)
83.3 (70.7–92.1)
30.0 (12.0–54.3)
1.19
0.56
76.3
40.0
62 12
45 (73%) 9 (75%)
80.0 (65.4–90.4) 55.6 (21.4–86.0)
47.1 (23.0–72.1) 66.7 (11.6–94.5)
1.51 1.67
0.42 0.67
80 83.3
47.1 33.3
20 54
16 (80%) 38 (70%)
81.3 (54.3–95.7) 73.7 (56.9–86.6)
25.0 (4.1–79.7) 56.3 (29.9–80.2)
1.08 1.68
0.75 0.47
81.2 80
25.0 47.4
34 40
28 (28%) 26 (65%)
89.3 (71.7–97.6) 61.5 (40.6–79.7)
50.0 (12.4–87.6) 50.0 (23.1–76.9)
1.79 1.23
0.21 0.77
89.3 69.6
50.0 41.2
14 60
12 (86%) 42 (70%)
75.0 (42.8–94.2) 76.2 (60.5–87.9)
50.0 (8.2–91.8) 50.0 (26.1–73.9)
1.50 1.52
0.50 0.48
90.0 78.0
25.0 47.4
4 70
0 (0%) 54 (77%)
– 75.9 (62.4–86.5)
– 56.3 (29.9–80.2)
– 1.74
– 0.43
– 85.4
– 40.9
6 68
5 (83%) 49 (72%)
80.0 (51.9–95.4) 75.5 (61.1–86.6)
0.0 52.6 (28.9–75.5)
0.80 1.59
– 0.47
80.0 80.4
0.0 45.5
Data are numbers, percentages, or mean (95% CI), as appropriate. AMI: Acute myocardial infarction; LR: likelihood ratio; PPV: positive predictive value; NPV: negative predictive value; CRF: chronic renal failure.
422
Letters to the Editor
Table 2 Sensitivities, specificities, likelihood values and predictive values of different cardiac markers for diagnosis of AMI.
FABP Myoglobin cTnI CK-MB
Cut-off (µg/L)
Sensitivity
Specificity
LR (+)
LR (−)
PPV
NPV
7.0 70 0.5 4.0
83.3 (70.7–92.1) 75.9 (62.4–86.5) 64.8 (50.6–77.3) 65.0 (40.8–84.5)
30.0 (12.0–54.3) 25.0 (8.8–49.1) 50.0 (27.2–72.8) 35.2 (22.7–49.4)
1.19 1.01 1.30 1.00
0.56 0.96 0.70 0.99
76.3 73.2 77.8 72.9
40.0 27.8 34.5 26.9
Data are numbers, or mean (95% CI), as appropriate. FABP: Fatty acid-binding protein; cTnI: cardiac troponin I; CK-MB: creatine kinase MB; LR: likelihood ratio; PPV: positive predictive value; NPV: negative predictive value.
from symptom onset to first blood sample was 2.2 h (IQR 1.5–2.9 h). Thirty-four patients (46%) had hypertension, 14 (19%) had diabetes, 4 (5.4%) had chronic renal failure (CRF), and 6 (8.1%) died during their hospital stay. Acute myocardial infarction was diagnosed in 54 (73%) individuals, of whom 39 (53%) had STEMI and 15 (20%) had NSTEMI. The non-AMI group consisted of 20 patients with a final diagnosis of hypertension, stable angina, pneumonia, paroxysmal ventricular tachycardia, femoral artery infarction and chronic renal failure. 3.1. Diagnostic performance of H-FABP immunotest Table 1 shows the diagnostic performance of H-FABP at presentation. The sensitivity and specificity of H-FABP at presentation were 83.3% and 30.0% respectively. Better test performance was found in elderly patients, females and patients with hypertension. Compared to younger patients, sensitivity was higher in older patients, but the inverse was observed for specificity. Females had higher sensitivity but lower specificity than males. Patients with diabetes did not affect the diagnostic performance.
The myocardial content of H-FABP (0.57 mg/g wet weight) is four- to five-fold lower than that of myoglobin (2.7 mg/g wet weight), yet the plasma reference concentration of H-FABP (1.8 µg/L) is 19-fold lower than that of myoglobin (34 µg/L). This means that after injury the tissue to plasma gradient is almost five-fold steeper for H-FABP than for myoglobin, making plasma H-FABP rise above its upper reference concentration at an earlier point after AMI onset, thus permitting an earlier diagnosis of AMI [1,7]. 3.4. Receiver operator characteristic curves for different cardiac markers The areas under the receiver operator characteristic (ROC) curves to distinguish AMI from non-AMI within 3 h after the onset of symptoms were 0.639 (95% CI: 0.490– 0.787) for H-FABP, 0.574 (95% CI: 0.425–0.723) for myoglobin, 0.499 (0.350–0.648) for CK-MB, and 0.505 (95% CI: 0.355–0.654) for cTnI. The area under the curve for H-FABP was significantly greater than those of the other cardiac markers within 3 h after the onset of symptoms. Thus, H-FABP has great potential as an excellent cardiac marker for diagnosis of AMI in the early phase.
3.2. Comparison of H-FABP and cTnI 4. Conclusion Of the 53 patients in whom both H-FABP and cTnI were positive, H-FABP was positive earlier than cTnI in 17 patients, whereas cTnI was positive earlier than H-FABP in 6 (p b 0.05). In this study, we demonstrated that H-FABP was positive significantly earlier than cTnI. All the patients presented to hospital within 3 h after symptom onset, when H-FABP might already be detectable, but not cTnI. Nonetheless, cTnI was elevated earlier in 11% of AMI patients. Variability in reporting of time delay after symptom onset may contribute to this finding.
In this study, we aimed to evaluate the accuracy of HFABP in a point-of-care setting for early diagnosis of myocardial damage in patients presenting to the ED suspected of AMI. H-FABP could not by itself diagnose AMI with adequately high accuracy, but when positive, it was usually faster than cTnI. In order to decrease the risk of falsely excluded patients with ongoing AMI, a combined measurement of two biochemical markers, an early one such as HFABP and a later marker such as troponins may provide the optimum diagnostic performance.
3.3. Sensitivities and specificities for different cardiac markers
Acknowledgements
The sensitivities and specificities of different cardiac markers are listed in Table 2. H-FABP gave the highest sensitivity (83.3%) for early exclusion of non-AMI patients, whereas cTnI gave the highest specificity (50.0%) for inclusion of AMI patients. H-FABP also had a higher sensitivity and specificity (30.0%) than myoglobin (sensitivity: 75.9%; specificity: 25.0%).
We thank the staff of the Emergency Department and the Department of Laboratory Medicine of Guangzhou First Municipal People's Hospital for their dedication and for diligently ensuring the highest possible level of data capture. We also thank Shenzhen Kang Sheng Bao Bio-Technology Co. Ltd. (Shenzhen, China) for donation of H-FABP immunotests (CardioDetect®).
Letters to the Editor
References [1] Glatz JFC, Van der Voort D, Hermens WT. Fatty acid-binding protein as the earliest available plasma marker of acute myocardial injury. J Clin Ligand Assay 2002;25:167–77. [2] Nakata T, Hashimoto A, Hase M, Tsuchihashi K, Shimamoto K. Human heart-type fatty acid-binding protein as an early diagnostic and prognostic marker in acute coronary syndrome. Cardiology 2003;99:96–104. [3] Chan CP, Sanderson JE, Glatz JFC, Cheng WS, Hempel A, Renneberg R. A superior early myocardial infarction marker. Human heart-type fatty acid-binding protein. Z Kardiol 2004;93:388–97. [4] Chan CP , Lehmann M, Renneberg I, et al. A Novel Credit-Card Style Assay for Beside Determination of Fatty Acid-Binding Protein. IVD Technology Magazine 2006;12:51.
0167-5273/$ - see front matter © 2008 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijcard.2008.01.049
423
[5] Chan CP, Cheng WS, Glatz JFC, et al. Early diagnosis of acute myocardial infraction using immunosensors and immunotests. J Anal Lett 2003;36:1987–2004. [6] Chan CP, Sum KW, Cheung KY, et al. Development of a quantitative lateral-flow assay for rapid detection of fatty acid-binding protein. J Immunol Methods 2003;279:91–100. [7] Glatz JFC, Kleine AH, Van Nieuwenhoven FA, Hermens WT, Van Dieijen-Visser MP, Van der Vusse GJ. Fatty-acid-binding protein as a plasma marker for the estimation of myocardial infarct size in humans. Br Heart J 1994;71:135–40.