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Test Code FRIFA Rifampin Level (PKRIF)


Specimen Required


Container/Tube: Red Top

Preferred: Red top tube

Acceptable: Serum gel tube

Specimen Volume: 2  mL

Collection Instructions: Draw blood in a plain, red-top tube(s). Separate serum from cells immediately by centrifugation and aliquot into a polypropylene or similar plastic tube. Send 2 mL of serum frozen in plastic vial.

Note:

1. The following information is required:

              A. Specimen Type (source)

              B. Dose (specify PO, IV, IM)

              C. Date and time of last dose (for IV start/end time)

 

2. If the time of last dose and the blood draw are not accurately recorded, accurate interpretation of the concentration is not possible.

 


Secondary ID

75628

Method Name

HPLC

Reporting Name

Rifampin Level

Specimen Type

Serum

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Frozen 365 days

Reject Due To

Hemolysis Mild OK; Gross reject
Lipemia NA
Icterus NA
Other Samples thawed greater than 6 hours.

Reference Values

mcg/mL

Interpretation

The target range for mycobacterial infections is 8 to 24 mcg/mL 2 hours after oral dose or 2 hours after the end of intravenous infusion. Samples drawn later than 2 hours after the dose will often display concentrations below the stated range.

 

Rifampin generally should be given as a single daily dose. If the patient is receiving 2 small daily doses, consider combining the doses and rechecking the concentration.

 

Rifampin absorption may be reduced by food. Take on an empty stomach if possible.

 

Rifampin does not have clear concentration-related toxicity and most patients tolerate concentrations above the stated range without difficulty.

 

Hepatic dysfunction may produce elevated rifampin concentrations. Rifampin concentrations greater than 50% above the range may warrant a dose reduction of 150 to 300 mg.

 

If the time of the dose and the blood draw were not accurately recorded, accurate interpretation of the concentration is not possible.

Performing Laboratory

National Jewish Health

Test Classification

The performance characteristics for this test have been validated by Advanced Diagnostic Laboratories at National Jewish Health. It has not been cleared or approved by the US Food and Drug Administration. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. This laboratory is certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA 88) as qualified to perform high complexity clinical laboratory testing.

CPT Code Information

80299

LOINC Code Information

Test ID Test Order Name Order LOINC Value
FRIFA Rifampin Level Not Provided

 

Result ID Test Result Name Result LOINC Value
Z5803 Dose Not Provided
Z5804 Date and Time of Last Dose Not Provided
Z5778 Rifampin Level 4021-2
Z5865 Specimen Type: Not Provided
Z5840 Comment: Not Provided

Day(s) Performed

Monday through Friday

Report Available

10 to 14 days