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HelpTest Code LABHCQ Hydroxychloroquine, Serum
Additional Codes
| Test Name in EPIC | EPIC Test Code | Mayo Test ID |
| Hydroxychloroquine | LABHCQ | HCQ |
Useful For
Monitoring serum hydroxychloroquine concentrations, assessing compliance, and adjusting dosage in patients
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name
Hydroxychloroquine, SSpecimen Type
Serum RedSpecimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube: Red top (gel tubes/SST are not acceptable)
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Collect specimen immediately before next scheduled dose.
2. Within 2 hours of collection, centrifuge, and aliquot serum into a plastic vial.
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum Red | Refrigerated (preferred) | 28 days | |
| Frozen | 28 days | ||
| Ambient | 21 days |
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Clinical Information
Hydroxychloroquine is an antimalarial drug used to treat or prevent malaria. It is highly effective against erythrocytic forms of Plasmodium but not effective against exoerythrocytic forms of parasites. Hydroxychloroquine is also used to treat symptoms of acute or chronic rheumatoid arthritis and systemic lupus erythematosus (SLE).
Adult doses range from 400 mg/week for suppressive therapy to 1200 mg/day for acute malaria attacks. Typical daily doses of 200 to 600 mg are used for SLE and rheumatoid diseases. Hydroxychloroquine has a long terminal elimination half-life in blood (>40 days), which exceeds that in serum. The oral bioavailability averages 75%.
Hydroxychloroquine accumulates in several organs, especially melanin-containing retina and skin. Mild to moderate overdose can result in gastrointestinal tract effects (ie, nausea, vomiting, and abdominal pain), headache, visual and hearing disturbances, and neuromuscular excitability. Acute hepatitis, cardiotoxicity, and retinopathy may occur with therapeutic doses. The effects of overdosage with hydroxychloroquine include headache, drowsiness, visual disturbances, convulsions, cardiovascular collapse, and respiratory arrest. Toxic retinopathy has also been associated with higher doses and longer duration of use.
Reference Values
For suppressive treatment of malaria, suggested plasma or serum concentrations should be >10 ng/mL.
For systemic lupus erythematosus, proposed serum target concentrations should be ≥500 ng/mL.
Interpretation
The serum concentration should be interpreted in the context of the patient's clinical response and may provide useful information in patients showing poor response, noncompliance, or adverse effects. Concentrations less than 106 ng/mL have been associated with noncompliance.
Cautions
Specimens that are obtained from serum gel tubes are not acceptable, as the drug can absorb on the gel and lead to falsely decreased concentrations.
Hydroxychloroquine is currently under investigational use for the prevention or postexposure prophylaxis and treatment of COVID-19; the safety and efficacy of its use have not been established.
Method Description
Samples are extracted with analyte detection by tandem mass spectrometry.(Unpublished Mayo method)
Report Available
3 to 7 daysSpecimen Retention Time
14 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
80220
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| HCQ | Hydroxychloroquine, S | 3684-8 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 64947 | Hydroxychloroquine, S | 3684-8 |
Day(s) Performed
Monday, Wednesday, Friday
Forms
If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.