What Are Denudation Pipettes and When Are They Used in IVF?

Denudation pipettes are precision-bore glass or plastic pipettes used in IVF laboratories to remove cumulus cells from oocytes after follicle aspiration. The process – denudation – is a critical step before ICSI (intracytoplasmic sperm injection), as the zona pellucida must be accessible and the cumulus-oophorus complex removed without damaging the oocyte. Denudation pipettes are sized in internal diameter, typically between 120 and 170 microns, with the choice of diameter driven by the size and maturity stage of the oocytes being processed.

What internal diameter denudation pipette should be used?

The standard approach is to start with a larger internal diameter – 170 microns is common – and progress to smaller diameters as cumulus cell removal proceeds. Starting too small risks mechanical damage to the oocyte through excessive aspiration force. Starting too large reduces the mechanical efficiency of cell removal. Most embryology protocols specify a stepwise approach using two or three bore sizes in sequence.

Are denudation pipettes single use?

In clinical IVF practice, denudation pipettes are single use per patient. Reuse between patients creates a cross-contamination risk that is incompatible with HFEA licensing requirements. Within a single patient’s treatment cycle, pipettes may be used for multiple oocytes from the same collection, provided they remain in the correct working medium and temperature environment.

What medium is used during denudation?

Denudation is performed in hyaluronidase solution, which enzymatically loosens the cumulus cells, followed by mechanical removal using the pipette in a protein-supplemented culture medium. The oocyte must remain within the correct temperature range throughout – room temperature deviation during denudation is a documented source of outcome variability.

The internal diameter of the denudation pipette is one of the smallest variables in an IVF cycle and one of the most consequential. A bore that is 20 microns too narrow for the oocyte being processed can damage the zona in the time it takes to notice resistance.

Cryolab supplies denudation, holding, and biopsy pipettes for IVF laboratories. Full range at cryolab.co.uk/product-category/denudation-biopsy-holding-pipettes/.