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22203 Haloperidol, Serum (HALO)

Haloperidol, Serum (HALO)
Test Code: HALOPSO
Synonyms/Keywords
Haldol®​ (Haloperidol), HALO
Useful For

​Optimizing haloperidol dosage

Monitoring patient compliance

Assessing toxicity

Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
Serum​ ​Red Top Tube (RTT) ​1 mL ​0.3 mL
Collection Processing Instructions

​Draw blood immediately before next scheduled dose.

Centrifuge and aliquot serum into plastic vial within 2 hours of collection.

Specimen Stability Information
Specimen Type Temperature Time
​Serum ​
Ambient 
​28 days
Refrigerate (preferred) 28 days
​Frozen ​28 days
Rejection Criteria
​Serum Separator Tube (SST)
Interference
​Potentially interfering drugs include hydroxyzine (interferes with haloperidol), tiagabine (interferes with reduced haloperidol), and quetiapine (interferes with internal standard resulting in artificially low haloperidol).
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Mayo Clinic Laboratories​ Tuesday ​2-5 days
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)​
Reference Lab
Test Information

​Haloperidol (Haldol) is a member of the butyrophenone class of neuroleptic drugs used to treat psychotic disorders (eg, schizophrenia). It is also used to control the tics and verbal utterances associated with Tourette syndrome and in the management of intensely hyperexcitable children who fail to respond to other treatment modalities.

The daily recommended oral dose for patients with moderate symptoms is 0.5 to 2.0 mg; for patients with severe symptoms, 3 to 5 mg may be used. However, some patients will respond only at significantly higher doses.

Haloperidol is metabolized in the liver to reduced haloperidol, its major metabolite.

Use of haloperidol is associated with significant toxic side effects, the most serious of which include tardive dyskinesia, which can be irreversible, extrapyramidal reactions with Parkinson-like symptoms, and neuroleptic malignant syndrome. Less serious side effects can include hypotension, anticholinergic effects (blurred vision, dry mouth, constipation, urinary retention), and sedation. The risk of developing serious, irreversible side effects seems to increase with increasing cumulative doses over time.

Reference Range Information
Performing Location Reference Range
Mayo Clinic Laboratories​
 
HALOPERIDOL
5-16 ng/mL
 
REDUCED HALOPERIDOL
10-80 ng/mL
Interpretation

Studies show a strong relationship between dose and serum concentration; however, there is a modest relationship of clinical response or risk of developing long-term side effects to either dose or serum concentration.

A therapeutic window exists for haloperidol, but some patients may respond to concentrations outside of this range. Patients who respond at serum concentrations between 5 to 16 ng/mL show no additional improvement at concentrations greater than 16 to 20 ng/mL. Some patients may respond at concentrations less than 5 ng/mL, and others may require concentrations significantly greater than 20 ng/mL before an adequate response is attained.

Because of such inter-individual variation, the serum concentration should only be used as one factor in determining the appropriate dose and must be interpreted in conjunction with the clinical status.

Although the metabolite, reduced haloperidol, has minimal pharmacologic activity, evidence has been presented suggesting that an elevated ratio of reduced haloperidol-to-haloperidol (ie, >5) is predictive of a poor clinical response. A reduced haloperidol-to-haloperidol ratio <0.5 indicates noncompliance; the metabolite does not accumulate except during steady-state conditions.

Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
80173
Synonyms/Keywords
Haldol®​ (Haloperidol), HALO
Ordering Applications
Ordering Application Description
​Centricity ​Haloperidol, Serum (56)
​Cerner ​None
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
Serum​ ​Red Top Tube (RTT) ​1 mL ​0.3 mL
Collection Processing

​Draw blood immediately before next scheduled dose.

Centrifuge and aliquot serum into plastic vial within 2 hours of collection.

Specimen Stability Information
Specimen Type Temperature Time
​Serum ​
Ambient 
​28 days
Refrigerate (preferred) 28 days
​Frozen ​28 days
Rejection Criteria
​Serum Separator Tube (SST)
Interference
​Potentially interfering drugs include hydroxyzine (interferes with haloperidol), tiagabine (interferes with reduced haloperidol), and quetiapine (interferes with internal standard resulting in artificially low haloperidol).
Useful For

​Optimizing haloperidol dosage

Monitoring patient compliance

Assessing toxicity

Reference Range Information
Performing Location Reference Range
Mayo Clinic Laboratories​
 
HALOPERIDOL
5-16 ng/mL
 
REDUCED HALOPERIDOL
10-80 ng/mL
Interpretation

Studies show a strong relationship between dose and serum concentration; however, there is a modest relationship of clinical response or risk of developing long-term side effects to either dose or serum concentration.

A therapeutic window exists for haloperidol, but some patients may respond to concentrations outside of this range. Patients who respond at serum concentrations between 5 to 16 ng/mL show no additional improvement at concentrations greater than 16 to 20 ng/mL. Some patients may respond at concentrations less than 5 ng/mL, and others may require concentrations significantly greater than 20 ng/mL before an adequate response is attained.

Because of such inter-individual variation, the serum concentration should only be used as one factor in determining the appropriate dose and must be interpreted in conjunction with the clinical status.

Although the metabolite, reduced haloperidol, has minimal pharmacologic activity, evidence has been presented suggesting that an elevated ratio of reduced haloperidol-to-haloperidol (ie, >5) is predictive of a poor clinical response. A reduced haloperidol-to-haloperidol ratio <0.5 indicates noncompliance; the metabolite does not accumulate except during steady-state conditions.

For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Mayo Clinic Laboratories​ Tuesday ​2-5 days
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)​
Reference Lab
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
80173
For most current information refer to the Marshfield Laboratory online reference manual.