An assay kit for the determination of Prekallikrein Activator (PKA) in Human Immunoglobulin Products.

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 32 IU/ml.

In conventional PKA assays of immunoglobulin fractions, high-test blanks can sometimes occur, with values higher than those of the test samples. To eliminate this problem this kit includes an additional blanking step to run with the existing method recommended by the European Pharmacopoeia (EP).

prekallikrein activator assay

  1. Human PreKallikrein (2x 2.5ml)
  2. Kallikrein Substrate PW-2302 (2x 1ml)
  3. PKA Standard 32 IU/ml (1x 1ml)
  4. Buffer A Concentrate (2x6ml)
  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. Quality Control (1x 0.5ml)
  10. Microtitre Plates (x2)

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

These are examples of a typical calibration curves.

prekallikrein activator assay prekallikrein activator assay


The assay kit is standardized against the 2nd International Standard for PKA.


Quality Control

A mid-level PKA control is provided with the kit to verify the validity of the calibration curve and sample results. The target range of PKA values for the kit control is batch specific and is provided in a table included with the kit.

Additional, high and low level accuracy controls are also available as separate products, and it is recommended that these are included 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




Sample 1 5.8 IU/ml 8.8%

Sample 2 15.5 IU/ml 8.2%

Intra-Assay (n=20)

Sample 1 5.8 IU/ml 6.3%

Sample 2 15.5 IU/ml 5.4%



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.