RESUMEN
INTRODUCTION: Platelet cholesterol (PC) could be used to assess "tissue" cholesterol of patients with vascular disease. However, the methods available so far to measure PC involve a complex extraction process. We developed a rapid method to measure PC and assessed its correlation with serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), LDL-C/HDL-C ratio, triglycerides (TG), and non-HDL-C. METHODS: We assessed repeatability (20 times, 3 participants) and reproducibility (8 times, 2 participants). A group of 47 healthy participants was studied. Blood was collected to analyze serum TC, LDL-C, HDL-C, and TG. Citrated blood was used to prepare a platelet pellet. A "clear soup" was produced (by disrupting this pellet using freeze-thaw and sonication cycles) and used to measure PC. RESULTS: Repeatability of PC showed a coefficient of variation (CV) of 4.8%. The reproducibility of PC over a period of 2 months was CV 7.5% and 8.1% (8 measurements for 2 participants). The PC of participants with serum LDL-C >2.6 mmol/L (treatment goal recommended by the National Cholesterol Education Program Adult Treatment Panel III) was 377 ± 120 µmol/10(12) platelets (n = 25). There was a significant correlation (Spearman, correlation coefficient) of PC (n = 25) with serum LDL-C (r(s) = 0.45, P = .02), LDL-C/HDL-C (r(s) = 0.45, P = .02), TG (r(s) = 0.43, P = .03), and non-HDL-C (r(s) = 0.53, P = .007). CONCLUSION: This technique of measuring PC has the advantage of being reproducible, fast, and simpler than previous methods. Thus, it may be useful for multiple sampling when investigating changes in PC in hypercholesterolemic patients. More extensive evaluation is necessary.
Asunto(s)
Plaquetas/metabolismo , Colesterol/sangre , Adulto , Plaquetas/química , HDL-Colesterol/sangre , LDL-Colesterol/sangre , Femenino , Humanos , Masculino , Proyectos Piloto , Activación Plaquetaria , Reproducibilidad de los ResultadosRESUMEN
BACKGROUND: The Department of Health launched a cardiovascular disease risk assessment initiative with particular reference to reducing health inequalities in ethnic minorities. Collaboration between HEART UK, Royal Free Hampstead NHS Trust and Hindu Temples resulted in vascular screening in North London. METHODS: Subjects of South Asian origin were screened. A full lipid profile and glucose were measured using a point of care testing (POCT) Cholestech LDX analyser (LDX). Venous samples were analysed in our hospital laboratory. RESULTS: The results (215 men; 191 women) were divided into tertiles and Bland-Altman plots were used to assess agreement. At high-density lipoprotein cholesterol (HDL-C) concentrations < 1.0 mmol/L the LDX underestimated values by -0.2 mmol/L (P<0.0001). At HDL-C concentrations >1.3 mmol/L this bias disappeared. For total cholesterol the concentration-dependent negative bias was evident at concentrations of < 4.1 mmol/L (P < 0.0001). This bias was less evident at higher concentrations. A similar pattern was seen for low-density lipoprotein cholesterol. There were also small variations in glucose and triglyceride values. However, there was excellent agreement in calculated cardiovascular disease risk using kappa analysis for JBS2, QRISK2, ETHRISK and Framingham (κ = 0.86, 0.92, 0.94 and 0.88, respectively). This was a high-risk population since 9.7-19.4% had a ≥ 20% 10-y probability of a vascular event depending on the risk engine and assay method used. The corresponding values for intermediate risk (11-19%) were 18.6-25.7%. CONCLUSIONS: There was a minimum mismatch irrespective of the type of risk calculator used. POCT measurements are adequate for the National Health Service Health Check.