Quality control material for plasma fibrinogen test produced from purified human fibrinogen

Plasma fibrinogen measurement is a routine laboratory procedure commonly performed on automated coagulation analysers. Its determination is quantitative, not quantitative. Yet, a lack of precision has been an issue for fibrinogen measurement. A control material derived from plasma comprises many proteins, inhibitors and fatty acids, any or all of which can interfere in the fibrinogen assay. This study has attempted to develop a quality control material using purified human fibrinogen and has compared measurement precision between both purified and plasma materials. Purified fibrinogen was prepared using Cohn fraction 1 and glycine precipitation. Purified fibrinogen clottability was greater than 95%, with no main plasma proteins, lipids or fibrinogen degradation products observed. Two purified control materials were lyophilized at normal (2.30 g lm1) and abnormal (1.20 g lm1) levels of fibrinogen concentration. Precision was evaluated using a liquid-type reagent, Thrombocheck Fib(L), on automated coagulation analysers. Coefficient of variation for within-run, intraday and between-day precision of the purified materials was 0.7-3.5%. In comparison, the coefficient of variation for plasma materials ranged from 1.2 to 5.3%. These results suggest that materials prepared from purified fibrinogen can be useful to laboratory quality control by improving overall precision of fibrinogen measurement and are applicable to automated coagulation analysers.

A Comparative Study Of Heparin And A Heparin Analogue In The Prevention Of Thrombosis In Patients With Gynaecological Cancer Under Radiotherapy

The frequency of thrombosis (D.V.T.) in patients treated for gynaecological cancer by combined external irradation and intravaginal radium application, as detected by the 125 I-fibrinogen-test, is considerable (43 % D.V.T.).84 patients undergoing radiotherapy were studied in a first controlled trial to assess the effect of 2×7500 U daily s.c. calcium heparin and 2×5000 U daily s.c. of a semisynthetic heparin analogue (SSHA) on the incidence of D.V.T. during therapy. 4 patients had to be excluded. The frequence of D.V.T. was 15 % (6/40) in the heparin group and 25 % (10/40) in the SSHA group. The difference was not statistically significant.Long term application of prophylaxis (regular radiotherapy lasts 4 weeks) causes discomfort to the patient because of the numerous subcutaneous injections.lt was the aim of a second trial to investigate the prophylactic efficacy of a single s.c. injection per day.80 patients were randomly allocated into two groups and received either 12500 U calcium heparin (n=40) or 12500 U SSHA (n=40). The incidence of D.V.T. was reduced to 15 % by a single heparin injection per day; in patients given SSHA the incidence was 17,5 %.The results presented indicate that SSHA is as effective as heparin in preventing D.V.T. during radiotherapy and that a single s.c. injection per day is sufficient.