Serum-separating tube Serum-separating tube Serum-separating tubes, also known as serum separator tubes or SSTs, are used in medical clinical chemistry tests requiring blood serum. SSTs are sometimes called "marble-top tubes," "tiger-tops," or "gold-topped tubes", referring to the stoppers which are either gold, red with a gold ring on top, or marbled red and grey. Marble-top tubes are also referred to as "tiger-tops" in some clinics. SPS tubes have a paler colour, sometimes leading confusion; these are known as "yellow tops" not "gold". Trademarked versions include Covidien "Corvac" tubes. They contain a special gel that separates blood cells from serum, as well as
Blood, Sweat & Tears (Blood, Sweat & Tears album) City. The studio had just taken delivery of one of the first of the model MM-1000 16-track tape recorders, built by Ampex. The new technology allowed for far more flexibility in overdubbing and mixing than the 4 and 8-track tape recorders which were standard in 1968. The album was among the very first 16-track recordings released to the public. An additional song, "Children of the Wind" was recorded for the album but was not included. It later appeared on the compilation, "The Very Best of Blood, Sweat and Tears: What Goes Up!" The album was selected for the 2006 book