Digitalis toxicity is characterized by gastrointestinal, neurologic and non-specific cardiac manifestations with striking similarities to the clinical picture of primary congestive heart failure (CHF) making diagnosis of chronic digitalis toxicity in particular relatively difficult. Serum digoxin measurement is today becoming a crucial subject of concern because of the narrow therapeutic window of digoxin besides increasing mortality and morbidity due to its intoxication. The present work is focused on evaluating the clinical value of serum digoxin concentrations (SDCs) in relation to appropriate assessment of chronic digitalis toxicity in cardiac patients. The current study was conducted in the form of a cross-sectional electronic medical record (EMR) review study of patients presently on continuous prescriptions for digoxin with there being zero gaps in therapy for at least 10 days prior to SDC result entered into the Online Analytical Toxicology Request Result (OTARR). There was also a complete clinical examination report as well as a review of the results of serum potassium concentration, liver and kidney functions. This study comprised of 217 adult patients (78 males and 139 females) with mean age ± SD (63.18 ±19 years). There were high concentrations of digoxin which led to unstable renal and liver functions. About 12% of the total cases showed an abnormal serum potassium concentration of electrolyte fluctuations. From this, one can conclude that a regular monitoring of serum digoxin concentration would be seen as mandatory for the verifica­tion of digoxin's therapeutic effects and then the subsequent prevention and early diagnosis of chronic toxicity