Which is the odd one out: a supermarket tin of baked beans, an airport suitcase or a hospital patient? The answer is the tin of beans, which is about 1,000 times less likely to be wrongly identified and mishandled than the suitcase or the patient, for each of which the risk is about 1 in 100. It is for this reason that the Hospital Authority is testing a supermarket style bar-code labelling system to help reduce mix-ups of patients' samples and specimens.
Sensational headlines in the international press, such as 'Embryo confusion: white couple have black twins' and 'Life-support blunder: hospital pulls plug on wrong patient' give the false impression that identification errors are spectacular and rare worldwide. In fact, misidentification of the cells, fluids, tissues, organs, limbs and bodies of patients is commonplace: the 'identity crisis' of modern medicine.
Reports in Hong Kong over the past year attest to mixed-up blood samples leading to transfusion error, mislabelled biopsies resulting in unnecessary mastectomy and wrong-patient prostate radiotherapy, mistaken implantation of prosthetics and confusion in the mortuary leading to cremation of the wrong body.
How reliably can we tell who's who and whose is who's in hospital? Let's start with the patient. The venerable hospital bracelet has been the mainstay of inpatient identification for decades. But, when scrutinised, wristband errors are detected in 7 per cent of cases: although in most cases the bands are simply missing, many others contain erroneous information and, astonishingly, 1 in 1000 patients is wearing a wristband belonging to someone else.
Wrong patient/site/operation errors have an incidence of about 1 per 25,000 procedures, and are the single commonest category reported by the Joint Commission on the Accreditation of Healthcare Organisations (which sets institutional health care standards in the US and internationally). Wrong-drug, wrong-patient mix-ups account for some 10 per cent of medication errors, another dominant cause of adverse events.
And then there are the tests. Mislabelling of laboratory blood samples occurs in about 1 in 500 instances. Studies show that up to 6 per cent of tissue pathology specimens are incorrectly labelled and that more than 4 per 1,000 surgical biopsy specimens are misidentified. Substantial patient harm results from at least 1 out of every 18 identification errors.