Hydroxychloroquine, Whole Blood

TEST: 504814
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CPT: 80220
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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 to 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.

   

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

TemperaturePeriod
Room temperature15 days
Refrigerated15 days

Causes for Rejection

Frozen specimens; gross hemolysis; clotted specimen

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 to 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