Doctors in the United States will from this month be able to test people’s
cholesterol levels with a small, disposable kit that uses only a couple
of drops of blood, takes just 15 minutes, yet is claimed to be as accurate
as laboratory tests.
The ChemTrak company of Sunnyvale, Cali fornia, makes the kits. It received
clearance from the US Food and Drug Administration (FDA) for the device
in March and began sales at the beginning of the month. The kits cost $6.25
each and can also be used by patients at home, when prescribed by a doctor.
Patients begin by pricking a finger to get one or two drops of blood,
which they drip into the kit’s sample well. Beneath the well, a filter separates
the blood into red cells and plasma, and deposits the plasma on a sample
pad. This step takes about one minute.
The patient then pulls a plastic tab which delivers 5 microlitres of
plasma into the system and mixes it with a buffering solution which helps
the plasma move onto chromatography strips. The lower part of the strips
contains two enzymes, cholesterol oxidase and cholesterol esterase, that
break the cholesterol down, and horseradish peroxidase, an enzyme which
reacts with the products to produce hydrogen peroxide. The amount of hydrogen
peroxide produced is proportional to the amount of cholesterol in the blood.
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The hydrogen peroxide then moves onto a chromatography strip which contains
a chemical that changes colour in the presence of hydrogen peroxide. The
length of strip that changes colour is thus proportional to the original
amount of cholesterol. The kit comes with a chart to convert readings in
millimetres on the strip into serum cholesterol levels. ChemTrak says that
tests of its meter against standard laboratory instruments show it to be
97 per cent accurate.
![Astronomers have long known that understanding how star clusters come to be is key to unlocking other secrets of galactic evolution. Stars form in clusters, created when clouds of gas collapse under gravity. As more and more stars are born in a collapsing cloud, strong stellar winds, harsh ultraviolet radiation and the supernova explosions of massive stars eventually disperse the cloud, and their light can bear down on other star-forming regions in the galaxy. This process is called stellar feedback, and it means that most of the gas in a galaxy never gets used for star formation. Researching how star clusters develop can answer questions about star formation at a galactic scale. Now, the state of the art has been further developed with both Hubble and Webb working together to provide a broad-spectrum view of thousands of young star clusters. An international team of astronomers has pored over images of four nearby galaxies from the FEAST observing programme (#1783), trying to solve this mystery. Their results show that it is the most massive star clusters that clear away their gaseous shroud the fastest, and begin lighting their galaxy the earliest. The team identified nearly 9000 star clusters in the four galaxies in different evolutionary stages: young clusters just starting to emerge from their natal clouds of gas, clusters that had partially dispersed the gas (both from Webb images), and fully unobstructed clusters visible in optical light (found in Hubble images). With Webb???s ability to peer inside the gas clouds, they were able to then estimate the mass and age of each cluster from its light spectrum. This image shows a section of one of the spiral arms of Messier 51 (M51), one of the four galaxies studied in this work, as seen by Webb???s Near-Infrared Camera (NIRCam). The thick clumps of star-forming gas are shown here in red and orange, representing infrared light emitted by ionised gas, dust grains, and complex molecules such as polycyclic aromatic hydrocarbons (PAHs). Within these gas complexes, each tens or hundreds of light years across, Webb reveals the dense, extremely bright clusters of massive stars that have just recently formed. The countless stars strewn across the arm of the galaxy, many of which would be invisible to our eyes behind layers of dust, are also laid bare in infrared light. [Image description: A large, long portion of one of the spiral arms in galaxy M51. Red-orange, clumpy filaments of gas and dust that stretch in a chain from left to right comprise the arm. Shining cyan bubbles light up parts of the gas clouds from within, and gaps expose bright star clusters in these bubbles as glowing white dots. The whole image is dotted with small stars. A faint blue glow around the arm colours the otherwise dark background.]](https://images.newscientist.com/wp-content/uploads/2026/05/13114322/SEI_296271016.jpg)
