TransFix is a CE marked solution that preserves leucocytes and leucocytic antigens in human peripheral blood for flow cytometric analysis. TransFix is used to extend the timeframe for sample analysis, providing flexibility in testing. Samples treated with TransFix are stabilised for up to 10 days when stored at 2-25°C, and for 4 days at temperatures between 25-37°C. TransFix is widely used for immunophenotyping purposes in hospitals and reference laboratories, as well as academic research institutions, pharmaceutical & biotechnology companies. TransFix can also be used with other cellular samples for research applications.

Cytomark's Blood Controls are reference samples that can be used during the set up and running of flow cytometers to provide quality assurance that equipment & processing procedures are performing optimally. These controls are produced from stabilised human whole blood with both normal and low CD4 counts. Each reference is provided with a QC certificate detailing the expected count and range for T cells (CD3+), T helper cells (CD3+CD4+), T suppressor cells (CD3+CD8+), NK cells (CD56+)and B cells (CD19+).

TransFix - a Cellular Antigen Stabilisation Reagent:

The intended use of TransFix is for immunophenotyping; when added to samples at the point of collection, TransFix immediately stabilises leukocytes for up to 10 days, providing flexibility in analysis. For human whole blood samples, Cytomark routinely QC test that the immunophenotypic profile is maintained for 10 days for cells with markers: CD3, CD4, CD8, CD16, CD19, CD45, and CD56. TransFix can also be used for monitoring CD4 and CD8 T-cell subsets of human immunodeficiency virus (HIV)-infected individuals using Flow Cytometry.

Stabilisation of cerebrospinal fluid is also possible using Cytomark's TransFix/EDTA CSF Sample Storage Tubes, which have been developed in collaboration with oncologists specifically for this purpose. Independent research has also been published on the stabilisation of bone marrow samples using the TransFix reagent.

Features and Benefits of TransFix:

Stabilises cell surface antigens for a minimum of 10 days at 2-25°C and for 4 days at 37°C
Easy to use, just add TransFix and mix by inversion
Ensures sample integrity during transportation between clinical sites
Eliminates the need for weekend and evening work
Reduces the impact of unexpected machine breakdown or staff shortages
Allows for repeat testing of samples without the need for patient recall and repeat phlebotomy
Greater efficiency in testing - allows for batching of samples prior to testing
Reduction in costs associated with the above advantages

Comparison of the leucocytic immunophenotype in normal human whole blood analysed immediately after collection, untreated after 11 days and stabilised with TransFix for 11 days:


Fig. 1 Diagrams A) and B) are flow cytometry density dot plots that demonstrate the normal leucocytic immunophenotype in a fresh sample of human whole blood. Granulocyte, monocyte and lymphocyte populations are all distinct (A) as are T Cells, NK Cells and B Cells (B). Diagrams C) and D) demonstrate the leucocytic immunophenotype in the same sample of human whole blood after 11 days of storage. leucocyte subsets, particularly monocytes are less distinct (C) and B Cells and NK Cells cannot be easily identified (D). Diagrams E) and F) demonstrate the leucocytic immunophenotype in the same sample of human whole blood after treatment with TransFix and storage for 11 days. All leucocyte subsets, including monocytes, B Cells and NK Cells can be clearly identified (E & F).

These images are taken from Cytomark's in-house Quality Control Tests (Cytomark, Buckingham, UK)


TransFix Applications

TransFix can also be used for a number of applications. Find out more about these applications on the Cytomark website by clicking on the links below:


Human Blood Stabilisation - Clinical Applications

Human Blood Stablisation - Research Applications

Cerebrospinal Fluid Stabilisation

Bone Marrow Stabilisation

Animal Blood Stabilisation

Immunostaining of Circulating Tumour Cells