Take care over blood brothers

Issues of human rights tend to stir the blood. Issues of mathematical probability don’t. But the latter needs to be the more compelling standard in the case of Warren Dempsey-Coy. His usually sought-after O-negative blood type is, in his case, unwanted by the New Zealand Blood Service, even when stocks are low.

He is a gay man in a longstanding, stable relationship, but falls foul of the rule that prevents donations from men who have had sex with another man in the previous 12 months, even if a condom was used.

This is indeed a case of discrimination – but, remember, that word has two distinct meanings. One is unjust or prejudicial treatment of different categories of people. The other is simply recognising and understanding the difference between one thing and another. That’s the case here.

Evidential, not moralistic, it comes down to a dispassionate, educated assessment of blood safety, made in the knowledge that testing practices, although improving, aren’t supremely reliable.

The NZ Blood Service acknowledges obligations to potential donors. Their rights and freedoms should be interfered with as little as reasonably possible. But that does not equate to a legal right to donate, and the service’s greater responsibility is to the safety of the vulnerable people who are receiving blood.

Problem being, it takes time for a newly acquired infection to be detected by a lab test and there’s a window during which donors can test negative but their blood could still be infectious.

There’s no getting around it that the risk doesn’t apply uniformly. Medical statistics show the risk of a detection failure is markedly greater from sexually active gay donors than their heterosexual counterparts.

A summary guide for the gay community from Auckland University in 2014 cited Australian mathematical studies that predicted the risk of failing to detect an HIV infection in donated blood is about 60 times greater for an average gay man who reports himself as monogamous than for an average heterosexual man with one new partner.

It’s futile to rail against this as unfair. And, albeit at something of a plodding pace, science is coming to the rescue. Testing practices have improved over the decades and the stand-down period has reduced from 10 years to five to the present 12 months.

It is reasonable that the question is asked – why can’t individual assessments be made in the case of each gay volunteer? That this doesn’t already happen might be interpreted as a presumption of promiscuity.

The service stresses that personal inquiries are an invasive process. Willing donors might well retort that medical matters are often invasive, so shouldn’t it be up to them to decide if they’re willing to face inquisition? But this overlooks tedious practicality. It’s the difficulty not only of collecting personal information, but assessing it confidently given that people can, for several reasons, be mistaken about their own conditions.

It is to Dempsey-Coy’s considerable credit, and many others, that they want to contribute to a real social need. But this requires informed confidence in the levels of risk involved for the recipients and it’s medical science, not social pressure, that must set the standard.

‘‘It comes down to a dispassionate, educated assessment of blood safety, made in the knowledge that testing practices, although improving, aren’t supremely reliable.’’