Biomedical subjects

N Blosser

Publications and source records attributed to N Blosser.

7 recordsLinked to original sources

PubMed1984

Effects of storage temperature and time before centrifugation on ionized calcium in blood collected in plain vacutainer tubes and silicone-separator (SST) tubes.

We studied the stability of ionized calcium and pH in samples stored at either room temperature or 4 degrees C, in centrifuged and uncentrifuged blood-collection tubes and in centrifuged tubes containing a silicone-separator gel (SST tubes). At room temperature, in uncentrifuged blood from healthy individuals, mean ionized calcium usually increased no more than 10 mumol/L per hour; at 4 degrees C it did not change detectably for 70 h. This stability was fortuitous, however: the concentrations of both hydrogen and lactate ions in these samples increased, apparently with offsetting effects on the concentration of ionized calcium. Blood stored for 70 h at 4 degrees C in centrifuged SST tubes, although showing a slightly greater change in ionized calcium, had less change of pH and no change in the ionized calcium corrected to pH 7.4. In 11 heparinized whole-blood samples from eight patients in intensive care, the mean change per hour in ionized calcium and pH after storage at room temperature was +10 mumol/L and -0.04 units, respectively.

Acute Disease↗

PubMed1983

An automated dry-slide enzymatic method evaluated for measurement of creatinine in serum.

We evaluated an automated dry-slide enzymatic method involving creatinine iminohydrolase for measurement of creatinine in serum with the Kodak Ektachem analyzer. The means (and SD) for three commercially available quality-control sera, analyzed during eight weeks, were 9.7 (1.0), 16.6 (0.9), and 61 (2.1) mg/L. The regression equation for 105 samples measured with the Technicon SMAC (x) and Ektachem Analyzers (y) was: y = (0.89 +/- 0.007)x + (1.7 +/- 0.3) mg/L and for 170 samples measured with the Beckman Astra (x) and Ektachem analyzers (y): y = (1.00 +/- 0.005)x - (1.9 +/- 0.16) mg/L. Sixty-one samples from renal-transplant patients showed nearly the same agreement. The enzymatic method had no interference from substances that interfere with many Jaffé methods for creatinine, including acetoacetate. The drugs cephalothin and cephoxitin did not interfere, but 5-fluorocytosine interfered significantly with creatinine in the Ektachem method. Values for several ketone-positive sera were 5 to 10 mg/L higher by the Astra relative to the Ektachem. Grossly hemolyzed or lipemic samples were analyzed without difficulty. We conclude that this enzymatic method for creatinine in serum has the speed and precision necessary for routine clinical laboratory use and, except for one drug, the method appears to be specific for creatinine.

Aminohydrolases↗

PubMed1973