Abstract
AIMS: To investigate the cause of turbidity in reconstituted lyophilised plasmas and to determine its effect on coagulometers. METHODS: The turbidities of 20 normal plasmas and 16 reconstituted lyophilised plasmas were determined by comparing a 1 in 4 dilution in distilled water with a standard suspension in an Aminco Fluorocolorimeter (American Instrument Co) in nephelometric mode. The turbidities of five other plasmas were determined before and after lyophilisation. The turbid components of fresh and reconstituted lyophilised plasmas were studied using electron microscopy. The effects of turbidity on five types of coagulometer were determined by adding varying concentrations of a turbidity enhancing material. RESULTS: Reconstituted lyophilised plasmas were more turbid than normal plasmas, because of agglomerated liposomes. Serum depleted of chylomicrons and very low density lipoproteins was not rendered more turbid by lyophilisation. Three out of five types of automated coagulometer tested gave activated partial thromboplastin times which were appreciably affected by plasma turbidity. One of the instruments was unable to detect a clot in a moderately turbid plasma. A second instrument gave results which were significantly affected by turbidity. Turbidity of the substrate plasma did not affect specific factor VIII assays in two types of coagulometer. CONCLUSIONS: Lyophilisation of plasma induces turbidity due to the agglomeration of lipids. Such turbidity can affect the results of coagulation tests. Suppliers of lyophilised plasmas should be aware of this problem.
Full text
PDF
Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Crowe J. H., Crowe L. M. Factors affecting the stability of dry liposomes. Biochim Biophys Acta. 1988 Apr 7;939(2):327–334. doi: 10.1016/0005-2736(88)90077-6. [DOI] [PubMed] [Google Scholar]
- Kroll M. H., Chesler R. Effect of serum lyophilization on the rate constants of enzymatic methods for measuring cholesterol. Clin Chem. 1990 Mar;36(3):534–537. [PubMed] [Google Scholar]
- Marcovina S. M., Adolphson J. L., Parlavecchia M., Albers J. J. Effects of lyophilization of serum on the measurement of apolipoproteins A-I and B. Clin Chem. 1990 Feb;36(2):366–369. [PubMed] [Google Scholar]
- Strauss G., Schurtenberger P., Hauser H. The interaction of saccharides with lipid bilayer vesicles: stabilization during freeze-thawing and freeze-drying. Biochim Biophys Acta. 1986 Jun 13;858(1):169–180. doi: 10.1016/0005-2736(86)90303-2. [DOI] [PubMed] [Google Scholar]
- Womersley C., Uster P. S., Rudolph A. S., Crowe J. H. Inhibition of dehydration-induced fusion between liposomal membranes by carbohydrates as measured by fluorescence energy transfer. Cryobiology. 1986 Jun;23(3):245–255. doi: 10.1016/0011-2240(86)90050-7. [DOI] [PubMed] [Google Scholar]