Which characteristic would indicate a serous effusion is exudative rather than transudative?

Which characteristic would indicate a serous effusion is exudative rather than transudative?

• A. Total protein: 6.5 g/dL
• B. Color: pale yellow
• C. Leukocyte count: 8 cells/μL
• D. Glucose: 70 mg/dL

Answer: (A)

When trying to tell an exudate from a transudate, the protein content in the serous fluid is the most informative clue. Exudates arise from inflammatory processes, infections, or malignancy that increase vascular permeability, so they carry more protein and other solutes. Transudates come from systemic factors like heart failure or hypoalbuminemia that lower fluid protein content. A fluid protein level of 6.5 g/dL is well into the high-protein range, consistent with an exudate. In contrast, transudates typically have much lower protein levels, often around 1–3 g/dL. So this high protein value is the best indicator that the effusion is exudative. Color, by itself, is not reliable for this distinction. A pale yellow appearance can occur in either type. A very low leukocyte count suggests a non-inflammatory process, which would not support an exudate. Glucose around normal levels is not diagnostic for exudates, since abnormal low glucose can occur in some exudates but is not definitive on its own.

When trying to tell an exudate from a transudate, the protein content in the serous fluid is the most informative clue. Exudates arise from inflammatory processes, infections, or malignancy that increase vascular permeability, so they carry more protein and other solutes. Transudates come from systemic factors like heart failure or hypoalbuminemia that lower fluid protein content.

A fluid protein level of 6.5 g/dL is well into the high-protein range, consistent with an exudate. In contrast, transudates typically have much lower protein levels, often around 1–3 g/dL. So this high protein value is the best indicator that the effusion is exudative.

Color, by itself, is not reliable for this distinction. A pale yellow appearance can occur in either type. A very low leukocyte count suggests a non-inflammatory process, which would not support an exudate. Glucose around normal levels is not diagnostic for exudates, since abnormal low glucose can occur in some exudates but is not definitive on its own.