Patent ID: 8544348

Claim:
A tube for separating a blood clot from serum in a blood sample, comprising: a chamber with a closed bottom and a sidewall extending upwardly from the chamber bottom, the sidewall defining a chamber opening for accessing a portion of the sample in the chamber; a sample inlet branch coupled to the chamber, the sample inlet branch having a sidewall defining a sample inlet branch opening for receiving a sample into the sample inlet branch, and the sample inlet branch having a bottom; and a slit positioned between the chamber and the sample inlet branch and extending from near the sample inlet branch opening toward the sample inlet branch bottom, the slit being tapered such that a width of the slit near the sample inlet branch opening is greater than a width of the slit near the bottom of the sample inlet branch, wherein the slit is sized and positioned so that, with a blood sample that includes serum and a blood clot having a size larger than the slit located in the sample inlet branch, a portion of the serum passes through the slit and into the chamber relying on gravity alone and the blood clot remains in the sample inlet branch.