[Stability of blood sedimentation rate following repeated mixing of the blood in a vacutainer tube (Seditainer)].
The stability of the sedimentation rate (read at 1 hour) was tested after repetitive mixing of the blood in the same Vacutainer Sedimentation tube ("Seditainer", Becton-Dickinson). The results of 275 sedimentation probes were collected by the nursing staff during routine clinical work on 5 internal medical wards. Sequential sedimentation tests with the same tube after mixing the blood by 6 inversions for the first run and 10 inversions for the second run, or 10 inversions for the first run and 6 inversions for the second, gave identical results. This shows that 6 inversions provide sufficient mixing of the blood. Our definition of one inversion includes turning of the tube axis by 180 degrees plus turning back to the original (vertical) position. If only 3 inversions were performed, the results were less consistent with those after 6 inversions. In 38 of 623 sedimentation runs the readings were too late by 7.6 +/- 4.7 minutes. The corresponding sedimentation rates were 113 +/- 24% of the control values read in time. In 17 of the 275 probes (6.2%) it was the first sedimentation run which was read too late. This shows that repetitions of the sedimentation test may be necessary in routine clinical work. The study clearly demonstrates that repetition is possible with the original sedimentation probe, which provides a reliable result if the blood is remixed by 6 inversions.
Medizinische Abteilung, Spital Neumünster, Zollikerberg.
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D001799:Blood Sedimentation; D006405:Hematology / Q000379:methods*; D006801:Humans; D013997:Time Factors
Stabilität der Blutsenkungswerte nach wiederholtem Mischen des Blutes in einem Vacutainer-Röhrchen (Seditainer).