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HelpTest Code LAB3708 Phenytoin, Adjusted, Plasma or Serum
Additional Codes
| Test Name in EPIC | EPIC Test Code | Mnemonic |
|---|---|---|
| ADJUSTED DILANT | LAB3708 | AJDIL |
Useful For/Utility
Use for the quantitative measurement of phenytoin in human serum or plasma. The measurements obtained are used in the diagnosis and treatment of phenytoin overdose and in monitoring levels of phenytoin to help ensure appropriate therapy.
Methodology
|
Profile Information: |
|
| Albumin | Phenytoin/Albumin Calculation |
| Phenytoin | |
Chemiluminescent Microparticle Immunoassay (CMIA)
Blood levels of phenytoin reflect only a total serum concentration of the drug. Only free unbound phenytoin has biological activity. Population groups that are predisposed to elevated free phenytoin levels include neonates, elderly persons, and individuals with uremia, hypoalbuminemia, or hyperbilirubinemia. These patients may exhibit signs of toxicity when drug levels are within the therapeutic range. This test will correct for low albumin levels.
Clinical Information
Blood levels of phenytoin reflect only a total serum concentration of the drug. Only free unbound phenytoin has biological activity. Population groups that are predisposed to elevated free phenytoin levels include neonates, elderly persons, and individuals with uremia, hypoalbuminemia, or hyperbilirubinemia. These patients may exhibit signs of toxicity when drug levels are within the therapeutic range. This test will correct for low albumin levels.
Specimen Requirements
Specimen must be refrigerated until test is performed.
Submit only 1 of the following specimens:
Preferred:
Specimen Type: Plasma
Container/Tube: Light-green top (lithium heparin gel)
Specimen Volume: 1 mL
Specimen Minimum Volume: 0.5 mL
Collection Instructions:
1. Spin down, separate plasma from cells within 2 hours of draw.
2. If plunger filters are used, immediate removal of plasma is indicated unless an air gap can be created between the device and specimen.
3. For oral dose, draw trough level unless otherwise specified. To monitor effect of oral loading dose, draw level 24 hours post dose. For intravenous (IV) dose, draw trough level. To monitor effect of IV loading dose, draw 2 to 4 hours after dose is infused. If toxicity is suspected, draw level when ordered STAT.
Additional Information:
1. Avoid repeated freeze/thaw cycles.
2. If extreme lipemia-use ultracentrifuged specimen.
3. Label specimen appropriately (plasma).
Alternate:
Specimen Type: Serum
Container/Type: Serum gel
Specimen Volume: 1 mL
Specimen Minimum Volume: 0.5 mL
Collection Instructions:
1. Spin down, separate serum from cells within 2 hours of draw
2. If plunger filters are used, immediate removal of serum is indicated unless an air gap can be created between the device and specimen.
3. For oral dose, draw trough level unless otherwise specified. To monitor effect of oral loading dose, draw level 24 hours post dose. For intravenous (IV) dose, draw trough level. To monitor effect of IV loading dose, draw 2 to 4 hours after dose is infused. If toxicity is suspected, draw level when ordered STAT.
Additional Information:
1. Avoid repeated freeze/thaw cycles.
2. If extreme lipemia-use ultracentrifuged specimen.
3. Label specimen appropriately (serum).
Specimen Transport Temperature
Refrigerate 5 days (48 hours/Ambient 8 2days OK/Frozen OK
Day(s) Test Set Up
Monday through Sunday
Performing Laboratory
Chemistry-
St. Joseph's Medical Center Lab
SMDC Clinical Lab, St. Mary's Hospital - Superior Lab, Sandstone Hospital Lab, Virginia Hospital Lab, Moose Lake Hospital Lab, Northern Pines Hospital Lab, Deer River Hospital Lab
Fargo Hospital Lab, Fosston Hospital Lab, St. Mary's - Detroit Lakes Hospital Lab,
Test Classification and CPT Coding
80185
Reference Values
PHENYTOIN
10-20 µ/mL
PHENYTOIN/ALBUMIN CALCULATION
Pheny/((0.2 x alb) + 0.1)
If suspected kidney dysfunction or creatine clearance is <25 mL/min use manual calculation with 0.1 covariable. Corrected calculation: Pheny/((0.1 x Alb) + 0.1)
See individual test listings for all other reference values.