Summary
In this study, we employed Particle Concentration Fluorescence Immunoassay (PCFIA),
for directly measuring both high and low molecular weight kininogens (HK and LK) in
human plasma. In 38 normal donors, the mean values for plasma kininogens were 93 mg/ml
+/- 19 SD, 82 mg/ml +/- 12 SD, and 175 mg/ml +/- 29 SD, respectively for LK, HK, and
TotK (the sum of LK and HK detected by their common heavy chains). Plasma completely
deficient in HK and LK was unreactive (<0.25 mg/ml) in all 3 assays whereas plasma
from a patient with Fitzgerald Trait had an HK value of 11 mg/ml, an LK value of 36
mg/ml and a TotK value of 59 mg/ml. The reagents can be prepared in advance and all
three kininogen determinations can be performed, using the same diluted sample, on
24 plasma samples, in triplicate, or 40 plasma samples, in duplicate, in less than
1 h. By performing all 3 kininogen determinations, it is possible to differentiate
cleaved from intact kininogens. This technique will facilitate the widespread screening
of kininogen levels in biological fluids of normal humans as well as of patients with
various diseases.
