Getting back into the rhythm of dialysis has not proved as irksome as I thought it might. When I was struck down with kidney failure 10 years ago, it demanded a root and branch change to my life and I was in the realm of the unknown. I knew nothing of kidney disease and I had a lifestyle I did not want to give up.
I had a thriving career back then, but once a serious illness takes grip, your ambitions shrivel up. Your mental energy is directed not on professional advancement but on mere survival. In some ways, it is liberating to have been cast out of the race.
Dialysis means four to six hours in hospital every other day. You have to plan your week around it, you have to change your diet, and you have to be very strict about the amount of fluid you take on board. Dialysis becomes the focus of your life and, however much you deny it, you are defined by your illness.
This was a shock to me back in 2000. But now I'm an old hand. It's almost as if I have never been away - the same faces have reappeared like ghosts from the past. The first day I walked into the dialysis unit, I saw the same people in the beds, the same nurses, the same support staff, and I was greeted like an old friend.
Some of the patients who dialysed with me eight years ago are now seriously ill. They cry out, they limp and wobble around the unit and sometimes just lie pained and motionless. "What is the point of going on?" moaned one old fellow over and over before sleep finally gave him - and the rest of us in the unit - a brief respite.
My wife, Rachel, is being tested to see if she can act as a donor for me. When we tell people what we are doing, most are amazed that there is even a chance that we could be compatible. The truth is, immuno-suppression drugs and transplant medicine in general is so sophisticated now that you no longer need the kind of match that you get from a blood relative.
There is also lots of evidence to show a transplant from a live donor is more successful than a transplant from a cadaveric one, even if the latter is a much better match. This is more obvious than you might think - by simply being alive, a kidney from a living donor is an instantly healthier prospect.
As well as testing our compatibility, the doctors need to be sure that Rachel's kidneys function well enough to withstand one being removed. They also want to check that she has no lurking health problems of her own.
Last week, she spent a whole day at the Royal Free hospital in
Hampstead. It started with a chest x-ray, and then moved on to having fluid with a radioactive trace injected into her arm. She then had a blood test every hour for three hours to see how much of it had been filtered out by her kidneys. After this came a scan to check that both her kidneys work equally well. Her heart was monitored with an ECG, and they also performed an angiogram of the blood vessels in her kidneys with a CT scanner.
I have had these kinds of tests innumerable times over the years and have become inured to being poked, prodded and pricked by medical staff while in various states of undress. The hospital can do what they like to me; I'm no longer squeamish or embarrassed about pulling my trousers down in front of strangers or urinating into plastic cups. But for Rachel, this - and those hospital gowns that flap open at the back - was a new and daunting experience.
We are both used to me being the one undergoing all the medical stuff, so it was strange to sit in the waiting rooms of various hospital departments and have her name called out instead of mine. It was strange to see her wince with a cannula in her arm, as usually I'm the one that's grimacing. Seeing her being the hospital patient suddenly made the concept of her actually going through with this surgery horribly real.
It became even more real after a call from the live donor team. So far, the tests look positive. We are definitely not related, which is always a relief for any husband and wife. More importantly, Rachel's blood group is compatible with mine and I don't have antibodies against her that would mean my body would reject her kidney.
The early results from the tests also show her kidneys appear to be functioning well. She still has more tests to do, but in a couple of weeks we should know one way or another if we have the final go-ahead.
• If you haven't joined the Organ Donor Register you can do so here: uktransplant.org.uk.