Subsection: Tests and Results
The tests that follow are blood, cerebral spinal fluid, and urine tests, then abdominal and chest
x-rays. Only those tests with values and corresponding actions that can be put concisely in
chart form are given. For other blood tests and how to interpret and respond to results, such
as bilirubin, see other units in this book.
Some tests, and guidelines for response to results, are given only here, not in any
A. Blood Gas Values (See also Unit 1, Oxygen, and Unit 2, Respiratory Distress, in this book.)
Blood gases measure the oxygen, carbon dioxide (CO2), and pH of blood. An arterial
blood gas (ABG) is needed to measure blood oxygen. However, a venous or capillary
blood gas provides a fair estimate of carbon dioxide, pH, and bicarbonate.
If a pulse oximeter is used, less frequent ABG determinations may be needed, depending
on the stability of oxygenation and the need to evaluate pH and CO2 levels.
Acceptable Blood Gas Values
Arterial Capillary Venous
Pao2 45-65 mm Hg* Po2 Unreliable Po2 Unreliable
pH 7.25-7.35 pH: 7.25-7.35 pH 7.25-7.35
Paco2 40-50 mm Hg Pco2 40-50 mm Hg Pco2 40-50 mm Hg
HCO32 19-22 mm Hg HCO32 19-22 mm Hg HCO32 19-22 mm Hg
*There is controversy among experts as to the appropriate range of Pao2 and oxyhemoglobin saturation. Know the
acceptable range for your hospital. Also, the target range will be different immediately following birth. (See Book I:
Maternal and Fetal Evaluation and Immediate Newborn Care, Unit 5, Resuscitating the Newborn.)