One Step Nucleic Acid Amplification (OSNA)

Histopathology


Description

Routine histological analysis of sentinel nodes to identify metastatic deposits is not possible within an intra-operative time frame and positive findings result in further surgery to clear the axilla and a delay in starting the most appropriate post-surgery treatment regimen for patients with metastatic disease. Conventional intra-operative analysis of the SLN can be performed via frozen section or touch imprint with a rapid H&E staining. Although this will produce an intra-operative result, the sensitivity of these methods is low because only a small proportion of the lymph node tissue can be investigated. As a result, there is a considerable risk of false-negative results. OSNA (One Step Nucleic Acid Amplification) is an alternative diagnostic approach which enables analysis of the whole lymph node in an intra-operative timeframe enabling an intra-operative clinical decision and removing the requirement for a second surgical procedure or treatment delay.


Sample Type

Intra-operative unfixed lymph node tissue


Reference Range

A calculated copy number of less than 250 copies/µl is considered a negative result (equivalent to no tumour or isolated tumour cells). A copy number between 250 and 5000 per µl correlates with a micrometastasis (equivalent to a tumour deposit between 0.2mm and 2mm across.) A copy number above 5000/µl is indicative of a macrometastasis (equivalent to a tumour deposit greater than 2mm across).


Turnaround Time

Within 1 - 2 hours


Testing Frequency

Daily


Please note: the above information is subject to change and we endeavour to keep this website up to date wherever necessary.

Your contact for this test

team

Stephanie Hibberd BSc (Hons), MSc, CSci, FIBMS

Laboratory Manager - Histopathology

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One Step Nucleic Acid Amplification (OSNA)