White blood cell count: a valuable tool for suspecting Cushing's syndrome

Area of Science:

• Endocrinology
• Hematology
• Diagnostic Medicine

Background:

• Cushing's syndrome (CS) diagnosis often lacks simple screening tools, leading to delayed detection and increased morbidity.
• Early identification of CS is crucial to mitigate associated health complications and sequelae.

Purpose of the Study:

• To assess the utility of glucocorticoid-induced white blood cell (WBC) count changes in screening for Cushing's syndrome (CS).
• To identify specific WBC parameters that can effectively raise suspicion for CS, facilitating earlier diagnostic workup.

Main Methods:

• A retrospective case-control study comparing WBC counts in 73 CS cases and 146 matched controls.
• Evaluation of ten WBC parameters, including leukocyte count, neutrophil and lymphocyte counts/percentages, and their ratios/differences.
• Calculation of the area under the ROC curve (AUC) for each parameter to determine diagnostic accuracy.

Main Results:

• All ten evaluated WBC parameters showed significant differences between CS cases and controls.
• Neutrophil-to-lymphocyte ratio (NLRp) and lymphocyte percentage (Lp) demonstrated the highest diagnostic accuracy (AUC: 0.89).
• A lymphocyte percentage (Lp) of 23.9% achieved 84.9% diagnostic accuracy for CS; specific combinations of Lp and leukocyte counts offered high positive and negative predictive values.

Conclusions:

• White blood cell (WBC) count analysis serves as an effective screening tool for raising suspicion of Cushing's syndrome (CS).
• This accessible and simple test can aid in the earlier diagnosis of CS, potentially before advanced clinical manifestations develop.