A chromogenic assay kit for the determination of Prekallikrein Activator (PKA) in Human Immunoglobulin Preparations.

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 50 IU/ml.

Conventional PKA assays of immunoglobulin fractions are often susceptible to high test blank levels, with blanks having higher values than those of the test sample. To eliminate this problem this kit includes an additional blanking step.

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 (2x 6ml)
  5. Buffer B
  6. Sample/Standard Diluent (2x 6ml)
  7. Immunoglobulin Pre-treatment Reagent. (1x 5ml)
  8. Blank Activity Blocking Reagent (BABR) (1x 1ml)
  9. 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 assay kit is standardized against the 2nd International Standard for PKA.

It is recommended that the PKA high and low positive accuracy controls designed for use with the Prekallikrein Activator (PKA) Assay IG 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 4.4 IU/ml 8.6%

Sample 2 12.7 IU/ml 8.3%

Intra-Assay (manual technique) n=20

Sample 1 4.4 IU/ml 6.5%

Sample 2 12.7 IU/ml 5.4%


Recovery from human immunoglobulin preparations spiked with known PKA concentrations, (1 to 20 IU/ml), yielded on average 102% (87-113%) of the theoretical expected value.