Which substrate is recommended by the IFCC for amylase testing?

The International Federation of Clinical Chemistry (IFCC) recommends the use of p-nitrophenyl maltoheptaoside as a substrate for amylase testing due to its specificity for amylase activity. This substrate is designed to provide a clear and accurate measurement of amylase concentration by generating a measurable product upon enzymatic reaction.

In tests involving amylase, the substrate should allow for a rapid reaction that can be quantitatively assessed, which is well achieved with p-nitrophenyl maltoheptaoside. The release of p-nitrophenol in the presence of amylase activity leads to a color change that can be measured spectrophotometrically, providing an effective means of quantification. This makes it suitable for clinical settings where precise levels of amylase are critical for diagnosing conditions like pancreatitis.

The other substrates listed do not align with the specific requirements for effective amylase testing as outlined by the IFCC. They may be utilized in other enzymatic tests but lack the specificity and efficiency needed for accurate amylase enzyme determination.