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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.
Expected Turnaround Time
7 - 10 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Related Documents
For more information, please view the literature below.
Therapeutic Drug Monitoring Options for Rheumatoid Arthritis Flyer
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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