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

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. The assay can be performed as rate method as recommended by the European Pharmacopoeia (EP), or by end point.

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 (1x6ml)
  5. Buffer B
  6. Sample/Standard Diluent (1x 6ml)
  7. Quality Control (1x 0.5ml)
  8. 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 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.