Which substances are best suited to measure interstitial fluid volume?: (A) Inulin and heavy water, (B) Inulin and 22Na, (C) Heavy water and 125I-albumin, (D) Inulin and 125I-albumin
Answer is D. Interstitial fluid volume= ECF volume - Plasma volume Inulin best indicator of ECF volume and 125I-albumin is most commonly used for plasma volume estimation