Test Catalog

Test Id : HCQ

Hydroxychloroquine, Serum

Useful For
Suggests clinical disorders or settings where the test may be helpful

Monitoring serum hydroxychloroquine concentrations, assessing compliance, and adjusting dosage in patients

Method Name
A short description of the method used to perform the test

Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.


Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Hydroxychloroquine, S

Lists additional common names for a test, as an aid in searching





Specimen Type
Describes the specimen type validated for testing

Serum Red

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

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


If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

0.5 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Serum Red Refrigerated (preferred) 28 days
Frozen 28 days
Ambient 21 days

Useful For
Suggests clinical disorders or settings where the test may be helpful

Monitoring serum hydroxychloroquine concentrations, assessing compliance, and adjusting dosage in patients

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

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
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

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 > or =500 ng/mL.

Provides information to assist in interpretation of the test results

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.

Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

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 coronavirus disease 2019 (COVID-19); the safety and efficacy of its use have not been established.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. McChesney EW BW, McAuliff JP: Laboratory studies on the 4-aminoquinoline antimalarials: II. Plasma levels of chloroquine and hydroxychloroquine in man after various oral dosage regimens. Antibiot Chemother (Northfield). 1962;12(9):583-594

2. Mok CC, Penn HJ, Chan KL, Tse SM, Langman LJ, Jannetto PJ. Hydroxychloroquine serum concentrations and flares of systemic lupus erythematosus: A longitudinal cohort analysis. Arthritis Care Res. 2016 Sep;68(9):1295-1302. doi: 10.1002/acr.22837

3. Durcan L, Clarke WA, Magder LS, Petri M: Hydroxychloroquine blood levels in systemic lupus erythematosus: clarifying dosing controversies and improving adherence. J Rheumatol. 2015 Nov;42(11):2092-2097. doi: 10.3899/jrheum.150379

4. Blanchet B, Jallouli M, Allard M, et al: Whole blood versus serum hydroxychloroquine levels for drug monitoring of patients with systemic lupus erythematosus: preliminary results of a pharmacological study. Ann Rheum Dis. 2019;78(2):1168-1169. Abstract SAT0188

5. Soichot M, Megarbane B, Houze P, et al: Development, validation and clinical application of a LC-MS/MS method for the simultaneous quantification of hydroxychloroquine and its active metabolites in human whole blood. J Pharm Biomed Anal. 2014 Nov;100:131-137. doi: 10.1016/j.jpba.2014.07.009

6. Wang LZ, Ong RYL, Chin TM, et al: Method development and validation for rapid quantification of hydroxychloroquine in human blood using liquid chromatography-tandem mass spectrometry. J Pharm Biomed Anal. 2012 Mar 5;61:86-92. doi: 10.1016/j.jpba.2011.11.034

7. Disposition of Toxic Drugs and Chemicals in Man. 10th ed. Biomedical Publications; 2014

8. Tett SE, Cutler DJ, Day RO, Brown KF: A dose-ranging study of the pharmacokinetics of hydroxy-chloroquine following intravenous administration to healthy volunteers. Brit J Clin Pharmacol. 1988 Sep;26(3):303-313

9. Gautret P, Lagier JC, Parola P, et al: Hydroxychloroquine and azithromycin as a treatment of COVID-19: results of an open-label non-randomized clinical trial. Int J Antimicrob Agents. 2020 Jul;56(1):105949. doi: 10.1016/j.ijantimicag.2020.105949

10. Kim SH: Comparison of lopinavir/ritonavir or hydroxychloroquine in patients with mild coronavirus disease (COVID-19). US National Library of Medicine (NLM). 2020. Accessed March 30, 2023. Available at clinicaltrials.gov/ct2/show/NCT04307693

11. Lu H: Efficacy and safety of hydroxychloroquine for treatment of pneumonia caused by 2019-nCoV (HC-nCoV). US National Library of Medicine (NLM). 2020. Accessed March 30, 2023. Available at clinicaltrials.gov/ct2/show/NCT04261517

12. Post-exposure prophylaxis for SARS-coronavirus-2. US National Library of Medicine (NLM). 2020. Accessed March 30, 2023. Available at clinicaltrials.gov/ct2/show/NCT04308668

Method Description
Describes how the test is performed and provides a method-specific reference

Samples are extracted with analyte detection by tandem mass spectrometry.(Unpublished Mayo method)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday, Wednesday, Friday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

3 to 7 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

14 days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test


Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.


LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
HCQ Hydroxychloroquine, S 3684-8
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
64947 Hydroxychloroquine, S 3684-8

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports