CST Technologies, SeraSub®

Description

Liquid, Protein-Free Serum Substitute For use in Manufacturing Clinical Chemistry and Immunological Standards and Controls.  This product has been proven effective for use with drugs of abuse and pregnancy (HCG), eliminating the need for lyophilization while stabilizing the product at room temperature.  Recovery of analytes is close to 100%.  Other uses include: Testing materials for urine contamination; Used for diaper and incontinence product development; and, car seat protection.

Human or mammalian blood products, such as human serum or plasma have been generally accepted and widely used as matrices for calibrators and reference controls since the advent of immunoassay techniques in the late 1970’s (Yellow, 1969), Typically, two to eight calibrators are used in an immunoassay for the purpose of constructing a dose-response curve (standard curve) by means of which the signal responses of reference controls and unknown specimens can be calculated in terms of concentration or mass units of a given analyte.

The ideal calibrator solution or matrix would be one whose composition is fully defined and would exactly match the composition of the unknown specimen except for the unknown analyte concentration. These conditions are rarely attainable in practice due to the wide variability of normal and abnormal physiological specimen composition.

A reasonable alternative would be a matrix which approximately matches the typical specimen composition, such as homologous human serum-based calibrators made from pooled analyte-free human serum for use in the assay of human serum specimens. However, some techniques utilized for removal of endogenous analytes (“striping”) frequently result in major alterations in the lipid and/or protein concentration and/or composition. Affinity chromatography, in contract, selectively removes the analyte without significantly altering the matrix. But, it is a costly procedure and is generally used only for removal of endogenous analyte present in extremely low concentrations.

A second, but less optimal alternative would be the use of calibrator matrices containing either a heterologous animal sera or human or bovine albumin fractions, in appropriate buffer formulations. Such protein-based matrices (including gelatin-based matrices as in U.S. Pat.#4,379,847) encompass virtually all calibrator formulations that are currently used in commercial immunoassay kits for the analysis of human and animal specimens. The undefined nature and lack of homogeneity of blood-based protein fractions frequently require extensive and costly screening and evaluation of materials from numerous sources.

SeraSub®, a newly developed, synthetic serum, offers the industry the optimal alternative solution to the problems of matrix compatibility.

SeraSub® is a synthetic polymer in buffered solution which is physically equivalent to serum and plasma with respect to:

Specific Gravity

Viscosity

Osmolality

SeraSub® does not contain any steroids, hormones, proteins, glucose, cholesterol, bilirubin, or any other interfering analytes. Therefore, the matrix is compatible with virtually all analytes.

SeraSub® contains a preservative which is both bacteriostatic and bactericidal. SeraSub® contains no azide. Preparations are available at various pH’s ranging from 6.8 to 9.2.

SeraSub® has been used to demonstrate its equivalency in several commercial products. Among these are:

T₄ Theophylline

Ferritin Phenobarbital

Digoxin THC

Cortisol Benzodiazepam

Testosterone Cocaine

Gentamicin Tobramicin

SeraSub® is a synthetic serum for use as a component in preparing standards and controls for in-vitro diagnostic tests. SeraSub® should be treated as any other component or ingredient that has to be qualified prior to use. SeraSub®, when used in this manner, does not require FDA approval for its use. A Device Master File for SeraSub® is pending. SeraSub® is manufactured under the strictest quality control guidelines to ensure quality and lot to lot uniformity.

Among the currently demonstrated applications for SeraSub® are:

Preparation of Calibrators (Standards)

Preparation of Controls

Use as the “O” standard for dilution studies (parallelism)

Use as a substitute base where needed

Prepare a concentrated solution of the analyte to be spiked in an aqueous or organic solvent. If an organic solvent is used, use the least possible amount of solvent for solution and spiking purposes. This will assure that SeraSub® will remain effective.