Tracking, witnessing, and the error-free laboratory

As we mentioned in the last issue of this newsletter an imperative of modern medicine is the development of control and safety process in order to protect the patient from accidental events during a medical procedure. Moreover, the certification ISO 9001:2008 clearly indicates the need to identify the “product” of medical interventions, just as any process, along the whole process in which it is involved. An obvious and important aspect of in vitro fertilization is the manipulation of gametes and embryos outside of the body, with the objective to improve pregnancy rates. An often underrated issue in the basics of ART is the importance of tracking gametes and embryos, in order to avoid mix ups with very serious consequences, as some recent cases have shown in the media. Professional and scientific societies in fact have published recommendations in order to have good medical practice in the ART laboratory. The European Society for Human Reproduction and Embryology (ESHRE), for instance, recommends to verify the identity of the patient before ovum pick-up, at semen collection, at the time of fertilization (IVF or ICSI), when cryopreserving embryos and before an embryo transfer. Moreover, ESHRE guidelines indicate that a double check should be in place at least for embryo transfer and freezing/thawing of embryos. In UK, the Human Fertility and Embryology Authority (HFEA) recommends in its Code of Practice that double checks should be incorporated in many of the same steps, including transport and destruction of gametes, and passage of gametes from dish to dish.

Some new technologies have been developed in order to make the checking and risk of mismatch less likely. One such example is the application of barcodes on samples vessels, straws, and dishes. The issue with this kind of labeling and checks resides in the possible mistakes in the barcode print, the need for a reader to be used, which brings about the unknown effect of the scanning light on the biologic materials, as well as the need to remember to read the barcode.The standard way of double checking consists in two persons acting as witnesses for the procedure, or the document, or the transcription of a name, etc… (hence the other name for this technique: witnessing). Witnessing in person is the standard which appears in the published guidelines, however it has some drawback. For instance, it is a system which implies the use of signature sheets and manual reporting, something not always accurate and desirable in large busy practices or in paperless environments. Moreover, studies have shown that manual reporting can suffer from the so called “ambiguous accountability”, by which a person would check less carefully a datum if they know that another person is also checking it.

An interesting alternative, still under development, is a direct tagging of oocytes and embryos by means of polysilicon barcodes which can be easily read under the microscope by the attending biologist (Novo et al, 2013; Novo et al 2014). A limitation of this method is its confinement to samples with a zona pellucida, therefore not applicable to sperm samples, which limits its ability to detect mismatches.

Labeling of samples vessels with radiofrequencies it’s another alternative, by which chips with embedded radiocodes are attached to dishes and tubes, and when a samples is moved from one vessel to the next, the new chip is informed with the old one information, thus guaranteeing a continuum of information. A drawback of this method, which is not present in the previously described two, is the “break” of the chain of controls when samples are frozen/thawed, as chips cannot be placed in liquid nitrogen.

Mistakes are a part of the human experience, and they are bound to happen at a certain rate (there is up to an estimated 10% of error rate in UK clinical procedures, for instance). For this reason, the goal of every ART clinic and labs should be to put in place several layers of controls, so that mistake is identified and corrected before the procedure is carried on, and before it has any consequence for the patient.


Rita Vassena
Scientific Director, Clinica EUGIN