In quantitative fecal fat testing, which step is used to quantify fat?

In quantitative fecal fat testing, which step is used to quantify fat?

• A. H2O2 and NADH
• B. Sudan Black B
• C. Extraction and weighing
• D. Enzymatic colorimetric assay

Answer: (C)

In quantitative fecal fat testing, you quantify fat by directly measuring the fat mass extracted from a known weight of stool. The gravimetric method uses an organic solvent (like ether) to extract fat from the stool, then the solvent is evaporated and the residual fat is weighed. This provides a direct mass of fat, which can be converted into a percentage of fat in the stool. Why this is the best approach: weighing the actual fat after extraction gives a true, quantitative measure of fat content, rather than just signaling its presence. The other options don’t yield a mass value for the total fat: H2O2 and NADH refer to enzymatic colorimetric reactions that aren’t used to quantify bulk fecal fat; Sudan Black B is a lipid stain used for visualization under a microscope, not for weighing fat; enzymatic colorimetric assays can measure specific lipid components but don’t provide the overall fat mass from a stool sample in the standard gravimetric method.

In quantitative fecal fat testing, you quantify fat by directly measuring the fat mass extracted from a known weight of stool. The gravimetric method uses an organic solvent (like ether) to extract fat from the stool, then the solvent is evaporated and the residual fat is weighed. This provides a direct mass of fat, which can be converted into a percentage of fat in the stool.

Why this is the best approach: weighing the actual fat after extraction gives a true, quantitative measure of fat content, rather than just signaling its presence. The other options don’t yield a mass value for the total fat: H2O2 and NADH refer to enzymatic colorimetric reactions that aren’t used to quantify bulk fecal fat; Sudan Black B is a lipid stain used for visualization under a microscope, not for weighing fat; enzymatic colorimetric assays can measure specific lipid components but don’t provide the overall fat mass from a stool sample in the standard gravimetric method.