Abstract
In this study, we correlated the lipid panel biomarkers (Total Cholesterol (TC), High-Density Lipoprotein (HDL) cholesterol, Low-Density Lipoprotein (LDL) cholesterol, Triglycerides (Trig)) measured in capillary blood with the biomarkers measured using venous blood. Additionally, we evaluated the stability of capillary blood measurements at 1, 3 and 5 days after collection and at different temperatures.
We found excellent correlation between the cholesterol levels measured using capillary blood vs venous blood. The TC, HDL, LDL, Trig and hs-CRP overall correlation coefficients were 0.978, 0.976, 0.995, 0.987 and 0.987 respectively. We also found that the cholesterol levels can be measured with very high accuracy even 5 days after collection (r=0.945, 0.952, 0.991, 0.976, 1.000) or if the sample is exposed to temperatures up to 32°C (r=0.953, 0.999, 0.940, 0.980, 1.000). Overall, we found that measuring cholesterol levels using capillary blood is highly accurate and stable.
Introduction
A comprehensive cholesterol test, also called lipid profile, is a blood test that measures the amount of cholesterol and triglycerides in blood. Such tests can help determine the risk of plaque buildup in the arteries that can lead to narrowed or blocked arteries (atherosclerosis). As the blood cholesterol rises, so does the cardiovascular disease risk. And if other risk factors are present such as smoking, high blood pressure or diabetes, the risk increases even further. The high-sensitivity C-reactive protein test can be used to determine the risk of developing cardiovascular disease. The level of CRP increases when there’s inflammation in the body and it is a risk factor for cardiovascular disease.
In this study, we evaluated how well the lipid panel biomarkers measured in capillary blood correlates with the biomarkers measured using venous blood. Additionally, we evaluated the stability of measurements at 1,3 and 5 days after collection and at different temperatures.
Methods
48 individuals (Aged 21-69, 58% females and 42% males) who provided informed consent were included in this study. Two samples were collected from each individual – A venous blood sample and a capillary blood sample. The photometric quantitative determination was performed on both these samples using the Alinity C system. All the venous blood samples were tested within 24 hours of collection. The capillary blood samples were measured at different time points and at different temperatures as shown in the table below:
Table 1. Table showing the time points and temperatures at which the tests were performed. Room temperature is 22°C.
Statistical Analysis: 4 combinations of timepoints and temperatures indicated in Table 1, a correlation coefficient is calculated by comparing the data from capillary blood samples to venous blood samples for each of the 5 lipid biomarkers.
Results
Table 2 below shows the correlation of cholesterol levels between venous blood and Capillary blood.
Table 2. Table showing the correlation coefficients of cholesterol levels at different timepoints and different temperature settings
Figures 1-15 below show the corresponding scatter plots showing lipid panel biomarker levels between venous blood and Capillary blood.
Figure 1. Scatter plot showing the relationship between the Total Cholesterol levels from capillary blood vs venous blood when measurements were taken within 1 day of sample collection at room temperature. (Unit: mmol/L)
Figure 2. Scatter plot showing the relationship between the HDL Cholesterol levels from capillary blood vs venous blood when measurements were taken within 1 day of sample collection at room temperature. (Unit: mmol/L)
Figure 3. Scatter plot showing the relationship between the LDL Cholesterol levels from capillary blood vs venous blood when measurements were taken within 1 day of sample collection at room temperature. (Unit: mmol/L)
Figure 4. Scatter plot showing the relationship between the Triglycerides levels from capillary blood vs venous blood when measurements were taken within 1 day of sample collection at room temperature. (Unit: mmol/L)
Figure 5. Scatter plot showing the relationship between the hs-CRP levels from capillary blood vs venous blood when measurements were taken within 1 day of sample collection at room temperature. (Unit: mg/L)
Figure 6. Scatter plot showing the relationship between the Total Cholesterol levels from capillary blood vs venous blood when measurements were taken within 1 day of sample collection at 32C. (Unit: mmol/L)
Figure 7. Scatter plot showing the relationship between the HDL Cholesterol levels from capillary blood vs venous blood when measurements were taken within 1 day of sample collection at 32C. (Unit: mmol/L)
Figure 8. Scatter plot showing the relationship between the LDL Cholesterol levels from capillary blood vs venous blood when measurements were taken within 1 day of sample collection at 32C. (Unit: mmol/L)
Figure 9. Scatter plot showing the relationship between the Triglycerides levels from capillary blood vs venous blood when measurements were taken within 1 day of sample collection at 32C. (Unit: mmol/L)
Figure 10. Scatter plot showing the relationship between the hs-CRP levels from capillary blood vs venous blood when measurements were taken within 1 day of sample collection at 32C. (Unit: mg/L)
Figure 11. Scatter plot showing the relationship between the Total Cholesterol levels from capillary blood vs venous blood when measurements were taken within 5 days of sample collection at room temperature. (Unit: mmol/L)
Figure 12. Scatter plot showing the relationship between the HDL Cholesterol levels from capillary blood vs venous blood when measurements were taken within 5 days of sample collection at room temperature. (Unit: mmol/L)
Figure 13. Scatter plot showing the relationship between the LDL Cholesterol levels from capillary blood vs venous blood when measurements were taken within 5 days of sample collection at room temperature. (Unit: mmol/L)
Figure 14. Scatter plot showing the relationship between the Triglycerides levels from capillary blood vs venous blood when measurements were taken within 5 days of sample collection at room temperature. (Unit: mmol/L)
Figure 15. Scatter plot showing the relationship between the hs-CRP levels from capillary blood vs venous blood when measurements were taken within 5 days of sample collection at room temperature. (Unit: mg/L)
Conclusion
Data collected from this study provide strong support that the cholesterol levels measured using capillary blood correlate excellently. The Total Cholesterol, High-Density Lipoprotein Cholesterol, Low-Density Lipoprotein Cholesterol, Triglycerides and high-sensitivity C-Reactive Protein overall correlation coefficients were 0.978, 0.976, 0.995, 0.987 and 0.987 respectively. This study also shows that the cholesterol levels from capillary blood are stable up to 5 days and at high temperature.
