This section provides information for tests with special considerations.
Tests Requiring Scheduled Collection
| Test | Required Scheduled Collection |
|---|---|
| 2 and 3 hour Glucose Tolerance | Monday-Friday, scheduled at Liberty Street Outpatient site only |
| Platelet Aggregation Study Vitalant Von Willebrand Profile | These specimens MUST be scheduled at Meadville Medical Center Laboratory, Liberty Street. Specimens for coagulation studies must arrive within 4 hours at the Vitalant Specialty lab in Pittsburgh. |
Therapeutic Drug Monitoring
Monitoring of Anticoagulation Therapies
- Warfarin: Monitoring of this anticoagulant therapy is best achieved by Protime (PT) testing and the subsequent calculation of the INR.
- Unfractionated Heparin: This anticoagulant is monitored by Anti-Xa and only while admitted in the hospital.
- Low Molecular Weight Heparin: This anticoagulant is monitored by Anti-Xa.
***Disclaimer: Currently there are no available techniques to monitor the “New” Oral Anticoagulants (NOAs) on the market i.e. Pradaxa (dabigatran), Xarelto (rivaroxaban), or Eliquis (apixaban). Based upon literature, it is suggested that patients wait 24 hours before beginning coagulation testing. Of note: The dose of these NOAs does not correlate well with the measured PT/INR and hence, anticoagulant testing when using these NOAs may be an unreliable guide to antithrombotic efficacy. ***
Make sure the drug is not hanging or infusing as you are drawing the level. If drawing through an existing catheter, make sure the line has been flushed appropriately.
Monitoring of Drugs at MMC
The following information has been reviewed and updated by MMC pharmacy:
| Drug | Therapeutic Range | Sampling Times |
|---|---|---|
| (APTT) Activated Partial Thromboplastin Time (Heparin®) | Normal 24-35 seconds Therapeutic range- 60.2-103 seconds | Per Heparin Protocol IV: 6 hours after initiation or changes in dose |
| Aminoglycosides Including: Gentamicin Tobramycin Amikacin – levels are sendouts and desired levels are different than gent & tobra trough/peak levels, but timing of the sample is the same. | Trough: Less than 2 mcg/mL Peak: 5-10 mcg/mL(depending on indication) Random: See Nomogram if EID | Trough: IV or IM therapy: within 30 minutes prior to dose Peak: IV: 30 minutes after 30 minute infusion IM: 1 hr after injection Random: 8-12 hours after 60 minute infusion for extended interval dosing (EID) |
| *Carbamazepine (Tegretol®/Carbatrol) | 4-12 µg/mL | Trough: 15 minutes prior to dose Peak: 6-8 hours post dose |
| Digoxin | 0.8-2.0 ng/mL | Trough: (Oral) 15 minutes prior or 12 hours post dose (IV) 15 minutes prior or 6-12 hours post dose |
| Phenytoin – Total (Dilantin)* Fosphenytoin (Cerebyx) Free Phenytoin (only in pts with altered protein binding-ex .uremia, hepatic disease, late pregnancy, postpartum or head injury) | 10-20 mcg/mL 10-20 mcg/mL 1-2.5 mcg/mL | ORAL Trough: 15 min prior to dose Peak: 6-8 hours post dose IV/IM Trough:15 min prior to dose Peak: 2 hours after IV dose; 4 hours after IM dose. |
| Lithium * | 0.5-1.5 mEq/L | Trough: 15 minutes prior to dose |
| Lovenox (enoxaparin) Therapeutic One (Dose?) Daily Two (Doses?) Daily Prophylactic | 1-2 IU/mL 0.6-1 IU/mL 0.2-0.5 IU/mL | Peak (Factor Xa level):Four hours after dose is administered |
| Phenobarbital * | 10-30 mg/mL >40 Critical | Trough: 15 minutes prior to dose |
| Prothrombin Time (INR) (Coumadin Therapy) | INR: Therapeutic 2-3 or 2.5-3.5, depending on indication | Preferable to keep the time of draws consistent 16-18 hours after dose. |
| Theophylline Liquid or fast release tab Slow-release product | 10-20 µg/mL | ORAL: Trough: just before dose Peak: 1 hour after dose IV: 30 minutes post loading dose, then 18-24 hours after initiation |
| Valproic Acid (Depakene®/ Depakote®) * | 50-100 µg/mL | Trough: 15 minutes prior to dose |
| Vancomycin Peak levels are only indicated in certain situations –contact pharmacy for more info | Trough: 10-15 mcg/mL For pneumonia, osteomyelitis, etc. 15-20 mcg/mL Peak: 30 - 40 mcg/mL | Trough: within 30 minutes prior to dose Peak: 1 hour after completion of 1 hour infusion |
*A trough level is appropriate for routine evaluation. For evaluation of toxicity, a peak sample is recommended. (REVISED by MMC Pharmacy 5/2005,11/2006, 1/2009, 3/2013)
References:
- Young L, Koda-Kimble M, eds Applied Therapeutics: The Clinical Use of Drugs Eighth Edition. Vancouver: Applied Therapeutics, 2005.
- Interpretation of Diagnostic Tests. Jacques Wallach, M.D. Lippencott Williams & Wilkins 2000
- Lexi-Comp Online, accessed January 2009
- Micromedex ® Drug Information, accessed January 2009
- Basic Clinical Pharmacokinetics 3rd edition. Winters ME. Applied Therapeutics, Inc Vancouver, WA.1994.