A chromogenic assay kit for the determination of Prekallikrein Activator in biological fluids.

Plasma Prekallikrein is activated to plasma kallikrein by Prekallikrein activator (PKA -FXIIa). The kallikrein formed releases p-nitroaniline (pNA) from the kallikrein substrate. The rate at which the pNA is released is measured photometrically at 405 nm in a microtitre plate reader.

The amount of pNA released is proportional to the amount of PKA present in the preparation up to a concentration of 25 IU/ml.

prekallikrein activator assay

  1. Human PreKallikrein (2x 2.5ml)
  2. Kallikrein Substrate PW-2301 (2x 5ml)
  3. PKA Standard 50 IU/ml (1x 1ml)
  4. Buffer A Concentrate (1x 6ml)
  5. Buffer B
  6. Sample/Standard Diluent (2x 6ml)
  7. Microtitre Plates (x2)

The kit should be stored at 2-8°C before use.

This is an example of a typical calibration curve.

prekallikrein activator assay


The Prekallikrein Activator (PKA) Assay kit is standardized against the 2nd International Standard for PKA. It is recommended that the PKA positive level 1 and 2 accuracy controls designed for use with the Prekallikrein Activator (PKA) Assay kit are run with each batch of tests.

PW51005 Just Positive™ Prekallikrein Activator (PKA) Control 5×0.5ml

PW52005 High Positive Prekallikrein Activator (PKA) Control 5×0.5ml


Inter-Assay (manual technique)

Sample 1 5.8 IU/ml 8.1%

Sample 2 12.5 IU/ml 7.6%

Intra-Assay (manual technique) n=20

Sample 1 5.8 IU/ml 6.3%

Sample 2 12.5 IU/ml 5.7%


The recovery from Human Albumin solutions spiked with known PKA concentrations (5 to 29IU/ml) yielded on average 98% (96-105%) of the theoretical expected value.