Therapeutic Drug Monitoring
 (Microbiology)

































Clotted sample container

Therapeutic Drug Monitoring
This is essential for patients being treated with aminoglycosides (gentamicin, amikacin, streptomycin),
vancomycin and flucytosine (5-FC) : adequate peak blood levels are necessary for a therapeutic effect,
trough levels indicate whether there is sufficient renal clearance to minimise toxicity. Antimicrobial Therpaeutic Drug Monitoring may be warranted with other drugs in special clinical situations.
These include checks on compliance (rifampicin for tuberculosis), absorption (itraconazole),
accumulation in patients with renal impairment (high dose co-trimoxazole for Pneumocystis;
penicillin, teicoplanin and ciprofloxacin in severe renal failure), and adequacy of dosage
in deep-seated infections such as endocarditis, osteomyelitis, non-inflammatory or chronic meningitis,
and syphilis (especially if these are treated with penicillin, amoxycillin, or teicoplanin - drug levels
may be measured directly, or 'back-titration' against the patient's own infecting organism may be used
to determine the bacteriostatic/bactericidal levels achieved in the blood).
PLEASE NOTE: VANCOMYCIN LEVELS - From 5th October 2015, Vancomycin results are approximately 11% lower than previously reported 

Investigation:                          Antibiotic Assay See Hospital Formulary

Inform lab before sending:     See Table:






Drug
Note:
Turnround Time::


Amikacin
Advance warning not required unless urgent
Contact Clinical Chemistry Laboratory


Teicoplanin
Advance warning not required unless urgent
Mon-Fri:48hrs - Reference Lab Referral


Gentamicin
Advance warning not required unless urgent
Contact Clinical Chemistry Laboratory


Tobramycin
Advance warning not required unless urgent
Contact Clinical Chemistry Laboratory


Vancomycin
Advance warning not required unless urgent
Contact Clinical Chemistry Laboratory


Benzylpenicillin
24 hour advance warning essential
Mon-Fri:48hrs - Reference Lab Referral


Ciprofloxacin
24 hour advance warning essential
Mon-Fri:48hrs - Reference Lab Referral


Cotrimoxazole
24 hour advance warning essential
Mon-Fri:48hrs - Reference Lab Referral


Cycloserine
24 hour advance warning essential
Mon-Fri:4 days - Reference Lab Referral


Flucytosine
24 hour advance warning essential
Mon-Fri:48hrs - Reference Lab Referral


Rifampicin
24 hour advance warning essential
Mon-Fri:48hrs - Reference Lab Referral


Moxifloxacin
24 hour advance warning essential
Mon-Fri:48hrs - Reference Lab Referral


Streptomycin
24 hour advance warning essential
Mon-Fri:48hrs - Reference Lab Referral


Others
24 hour advance warning essential
Please discuss with the laboratory





Specimen type:                       Whole Blood

Volume:                                   5-10 ml (For neonates 0.5 – 2ml of blood in a small heparin tube will suffice)

Ideal time to take specimen:   Pre-dose levels up-to 30 mins before next dose is administered

                                                Post-dose levels 1 hour after the dose has been administered 






Labelling:
                 Specimens must have:

  • Unit number/A+E number or date of birth
  • Full name (forename and surname)
  • Specimen type ( e.g. Pre-dose, Post –dose or Random)
  • Date & time of collection 

                 Request forms must have:

  • Unit number/A+E number or date of birth
  • Full name (forename and surname)
  • Date of Birth
  • Location
  • Specimen type ( e.g Pre-dose, Post –dose or Random)
  • Antibiotic dosage and frequency
  • Date and Time of collection

Transport to the laboratory: If transport is delayed then refrigerate sample.

Reference Ranges: See Hospital Formulary:

Additional information: Post dose teicoplanin levels are NOT normally indicated.
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