Reference intervals for 18 clinical chemistry analytes in fetal plasma samples between 18 and 40 weeks of pregnancy.

null hypothesis was that temperature had an effect on the test results. The data shown in Table 1 also reject this hypothesis and suggest that temperature alone does not affect the tested variables. There are almost no arguments against the value of umbilical artery blood gases analysis taken postpartum in cases indicated by ante-and intrapartum events. Because blood is a living tissue, it has been argued that metabolic changes will continue at room temperature, therefore making it necessary to examine the blood immediately or to minimize the metabolic changes by reducing the temperature [5]. We carried out the present study to examine the validity of blood gas measurements under the different situations that may occur in a busy practice, where shortage of staff and equipment, compounded with a difficult delivery, may sometimes prevent immediate or appropriate storage/shipment of the blood sample to the laboratory. Our data indicate that a time of 1 h, alone or in combination with temperature (with or without refrigeration), does not significantly affect the results for pH, Pco 2 , and Po 2 of arterial cord blood. Our conclusions were similar to those found in previous studies. However, our study examined the whole range of blood gas parameters, in comparison with only selected parameters in other studies. Moreover, we used standardized sampling, i.e., blood taken into heparin-containing plastic syringes directly from the umbilical cord, whereas other studies examined blood taken with or without heparin, directly or indirectly from the cord or from a cut segment. Finally, our study is among the few that assessed reproducibility. All in all, our study seems to be among the most complete of its kind. The results we found provide two important clinical conclusions. First, the clinical laboratory should accept an umbilical cord blood sample within 1 h after storage at room temperature. Second, although uniformity of sampling (using minimally preheparinized syringes) and shipment procedures are to be preferred, the clinician working in the busy delivery room where no one is available to optimally handle the blood sample can be reassured that if the blood sample is taken immediately, he or she does not need to arrange for immediate shipment or for special storage. As long as the blood sample is examined within 1 h, the results are still valid for both clinical and medicolegal purposes. Changes of pH-values during storage of fetal blood samples. The intrauterine biochemical assessment of the …