Test Details
Methodology
Electrochemical (pH meter)
Result Turnaround Time
2 - 4 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
This test is used to determine pH of body fluid.
Special Instructions
Specify body fluid source on the request form.
This test is not appropriate for measurement of pleural fluid pH. Due to sample instability and a requirement to transport the specimen, that measurement should be made locally using a blood gas analyzer.
Limitations
This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.
Custom Additional Information
pH >7.3 is in general a feature of transudates. Low pH and low glucose together are found with loculated effusion or with empyema.1 Effusions related to lupus erythematosus generally have a pH >7.35.2
Effusions of tuberculosis usually have pH <7.3,2 usually with increased lymphocytes.
In bacterial peritonitis pH is decreased: cutoff <7.35 is useful, especially with PMNs >500/mm.1 The mean pH of infected ascitic fluid is reported as 7.24. The arterial-ascitic fluid pH gradient >0.10 with >500 PMNs is described as virtually diagnostic of bacterial peritonitis.3
Reduction of pH and in some, but not all, series increments of PMN counts may be found also with peritoneal metastases.3,4
Specimen Requirements
Specimen
Serous fluids (pericardial, ascitic) or synovial fluid
Volume
5 mL
Minimum Volume
1 mL
Container
Sample should be collected anaerobically. A lithium heparin tube to prevent clotting should be used, especially if the syringe has not been rinsed with heparin.
Collection Instructions
A syringe rinsed with 0.2 mL heparin, 1:1000 may be used; collect anaerobically. If the specimen is collected in a syringe, all air should be expelled and the needle sealed and capped.
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 14 days |
Refrigerated | 14 days |
Frozen | 14 days |
Freeze/thaw cycles | Stable x3 |
Reference Range
Not established
Storage Instructions
Room temperature
Causes for Rejection
Pleural fluid, spinal fluid (CSF), urine, feces or blood specimen received; icteric samples
Footnotes
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 011254 | pH, Body Fluid | 2748-2 | 011254 | pH, Body Fluid | 2748-2 | |
| Order Code | 011254 | |||||
| Order Code Name | pH, Body Fluid | |||||
| Order Loinc | 2748-2 | |||||
| Result Code | 011254 | |||||
| Result Code Name | pH, Body Fluid | |||||
| UofM | ||||||
| Result LOINC | 2748-2 |