Umbilical Cord Blood Gas Pairs with Near-Identical Results: Probability of Arterial or Venous Source.

Objective: In studies of concomitant arterial-venous umbilical cord blood gases (CAV-UBGs), approximately 10% of technically valid samples have very similar pH and/or pCO values and were probably drawn from the same type of blood vessel. Without a way to objectively determine the source in these cases, it has been argued that most of these same-source CAV-UBGs are venous because the vein is larger and more easily sampled than the artery. This study aimed to calculate the probability of an arterial (ProbAS) or venous source (ProbVS) of same-source CAV-UBGs in the clinically and medicolegally important pH range of 6.

Non-linearity in lipase assays: A multicentric comparison on different analysers.

Objectives: Non-linearity in lipase assays and the ensuing gaps in results distribution have been described on Roche analysers, but have yet to be studied on other analysers.

Design And Methods: Eighteen lithium-heparinized plasma pools of lipase activities decreasing from 1700 to <4 U/L were prepared for multicentric evaluation on several analysers. Non-linearity was modelled as the difference between the polynomial regression of lipase activities depending on relative dilutions over the primary measuring range, and the linear regression of the same variables above the manufacturer's limit of linearity (MLL).

Umbilical cord blood gases: probability of arterial or venous source in acidemia.

Objectives: Umbilical cord blood gases (UBG) may be a critical element in the assessment of a depressed newborn infant but in some cases the arterial or venous UBG source is uncertain making clinical and/or medical-legal interpretation difficult. Objective: to estimate the probability of an arterial (ProbAS) or venous (ProbVS) UBG source depending on blood gas parameters in acidemic cases.

Methods: A total of 56,703 pairs of concomitant arterial and venous (CAV) UBG results assayed over an 8.