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Hydroxychloroquine, Whole Blood

CPT: 80299
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Synonyms

  • HCQ for long-term retinopathy evaluation
  • HCQ for lupus and other autoimmune patients
  • Plaquenil

Special Instructions

This assay which measures whole blood HCQ is the preferred assay for evaluation of lupus and other autoimmune patients on daily hydroxychloroquine.

This test should be ordered after 3 - 6 months of daily HCQ to assess daily dosage in lupus where drug action and efficacy are cumulative. In lupus, several weeks or months may be required to reach maximum therapeutic benefit that correlates with whole blood HCQ measurement.

This assay is not approved for NY state clients.


Expected Turnaround Time

10 days


Specimen Requirements


Specimen

Whole blood


Volume

1.0 mL


Minimum Volume

0.4 mL (Note: This volume does not allow for repeat testing.)


Container

Lavender-top (EDTA) tube


Collection

Collect whole blood into lavender-top (EDTA) tube. Refrigerate immediately.


Storage Instructions

Refrigerate.


Stability Requirements

Temperature

Period

Room temperature

15 days

Refrigerated

15 days


Causes for Rejection

Frozen specimens


Test Details


Use

This assay measures the whole blood concentration of hydroxychloroquine. Monitoring HCQ may improve adherence, and whole blood HCQ concentrations may be useful in titrating dose to achieve maximal clinical benefit in lupus while minimizing long-term retinal toxicity in lupus and other chronic autoimmune diseases.

In lupus, RA and other autoimmune diseases, several weeks or months may be required to reach maximum therapeutic benefit that correlates with whole blood HCQ measurement.


Limitations

This test should be ordered after 3 - 6 months of daily HCQ to assess daily dosage in lupus, RA and other autoimmune diseases.


Methodology

LC-MS/MS


References

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):2092-2097.26428205
Koneru S, Shishov M, Ware A, et al. Effectively measuring adherence to medications for systemic lupus erythematosus in a clinical setting. Arthritis Rheum. 2007 Aug 15;57(6):1000-1006.17665465
Petri M, Elkhalifa M, Li J,Magder LS, Goldman DW. Hydroxychloroquine Blood Levels Predict Hydroxychloroquine Retinopathy. Arthritis Rheumatol. 2020 Mar;72(3):448-453.31532077

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
504814 Hydroxychloroquine, WB 95921-3 504824 Hydroxychloroquine, WB ng/mL 95921-3

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CPT Statement/Profile Statement

The LOINC® codes are copyright © 1994-2021, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee. Permission is granted in perpetuity, without payment of license fees or royalties, to use, copy, or distribute the LOINC® codes for any commercial or non-commercial purpose, subject to the terms under the license agreement found at https://loinc.org/license/. Additional information regarding LOINC® codes can be found at LOINC.org, including the LOINC Manual, which can be downloaded at LOINC.org/downloads/files/LOINCManual.pdf