Test Code PHFL 
Test pH, FLUID 
Methodology Ion-Selective Electrode (ISE) 
Description For pH testing on all body fluid types EXCEPT Gastric Fluid 
Specimen 1.0 mL BAL/Lo Hep Syringe*, minimal acceptable volume in a syringe is >/= 0.095 mL BAL/Lo Hep syringe (*Syringes in use are 1ml concord/Portex syringes that contain 15 IU of dry Lithium Heparin as well as 3ml syringes with 23.5 IU. Minimum sample volumes are dependent on hematocrit of sample)

OR >3.5 mL in a 4ml Lith Hep tube (dk green LiHep whole blood tube)

OR >1.5 mL in a 2ml Lith Hep tube (transparent green LiHep whole blood tube)

OR >2.5 mL in a 5 mL SST (not clotted)

OR >3.5 mL in a 6.0 mL Red top (not clotted)

The optimal specimen type for a pH on body fluids is a balanced heparin syringe. Immediately after drawing the sample, all air should be expelled from the syringe, the syringe capped securely, thoroughly mixed to avoid clots and kept in an ice slurry, if not delivered to the lab immediately after collection. It should be analyzed within 30 minutes of collection but is stable up to 4 hours unless in the presence of a high WBC or Platelet count, in which case testing should be performed immediately. In lieu of a heparinzed syringe, lithium heparin whole blood tubes (dark green or transparent green), red top or SST (gold top) tubes are acceptable provided testing is completed within 30 minutes or up to 4 hours on ice.


Reference Values Varies with fluid type 
Analytic Time 1 Day 
Day(s) Test Set Up Monday through Sunday 
CPT Code(s) 83986