Old and New

Maybe I am presenting a strange Blipfoto contribution today, but I am (professionally) interested in instrumentation such as this!

For reasons that do not matter here, I have to monitor how rapidly my blood coagulates (INR). I have had an instrument for home testing for roughly 6 years.

Unfortunately, the manufacturers have ceased production of the test strips for the machine I have been using hitherto. I have therefore had to obtain the newer version. In today's photograph, you can see the old and the new together.

The new one is certainly much smaller than the old one, and here nestles easily within just one side of the case for the latter! And it's more convenient, because the test strips do not need to be refrigerated, and calibration is built in.

For those interested (remember I'm an anorak*), the old strips used a test based on rabbit brain thromboplastin, and photoelectric detection of inhibition of vibration of magnetic particles, wobbled around by an AC magnetic field. The replacement strips employ human recombinant thromboplastin, together with electrochemical detection of the coagulation response.

Very clever stuff indeed!

*Self-awareness moment: here's Wikipedia's lead on "anorak".

"In British slang an anorak is a person who has a very strong interest, perhaps obsessive, in niche subjects. This interest may be unacknowledged or not understood by the general public. Although the term is often used synonymously with geek or nerd, the Japanese term otaku or the American term "fanboy/fangirl" are probably closer synonyms.