The role of race in medical decision-making has been a contentious issue. Insights from history and population genetic studies suggest considerations of race as a differentiating marker for medical practices can be influenced by systemic bias, leading to serious errors. This might impact treatment of complex diseases such as cardiovascular disease (CVD). We seek to identify instrumental variables and test whether diagnoses (Dx) and treatments impacting coronary thrombosis (CT) are racially linked. Using data from UK Biobank, we found minimal, non-significant racial differences in odds ratio (OR) between cardiac fatalities and among CVD diagnoses in living patients. Genetic classification vs. racial identification of Black British (BB) showed no significant differences in CVD treatment. Among hyperlipidemia patients, BB tended to suppress prescription for statins and fibrates, even among older patients (OR=0.615, 95%CI: 0.385-0.983, p-value=0.04), but lipids-level differences immediately prior to the first prescription showed no significant racial bias. Using polygenic risk scores (PRS) for CT yielded higher OR (2.198, 95%CI: 1.725-2.801, p-value=1.8×10^-10) for BB for higher PRS deciles compared to CT Dx OR for BB. Higher PRS deciles also showed increased risk for BB. Therefore, PRS can be a useful proxy for Dx yielding better predictive power for underrepresented minorities.