16 October 2023
: Case report 
Bilirubin Elevation Caused by Naproxen Overdose: A Case Report Highlighting Laboratory Interference
Unusual clinical course, Unexpected drug reaction
Olivia Heutlinger1DEF*, Tobin Mathew1DEF, Dylann Fujimoto
1DEF, Vishnu Bharani1E, Rebecca Yamarik2DE, Samuel Baz2E
DOI: 10.12659/AJCR.941267
Am J Case Rep 2023; 24:e941267
Table 1. Laboratory findings of the patient on admission. Bolded values represent the abnormal findings.
| Laboratory test | Patient value | Reference range |
|---|---|---|
| Sodium (mEq/L) | 136 | 135–145 |
| Potassium (mEq/L) | 3.5 | 3.5–5.0 |
| Chloride (mEq/L) | 102 | 95–105 |
| Bicarbonate (mEq/L) | 28 | 24–32 |
| Blood urea nitrogen (mg/dL) | 8 | 5–25 |
| Creatinine (mg/dL) | 0.79 | 0.70–1.40 |
| Glucose (mg/dL) | 60–100 | |
| White blood cell (K/mm) | 7.85 | 4.00–11.00 |
| Hemoglobin (g/dL) | 13.5–17.0 | |
| Hematocrit (%) | 39.1 | 39.0–50.0 |
| Mean corpuscular volume (fL) | 88.7 | 82.0–98.0 |
| Platelet (K/mm) | 348 | 150–400 |
| Calcium (mg/dL) | 8.8 | 8.5–10.5 |
| Total Protein (g/dL) | 6.6 | 6.0–8.5 |
| Albumin (g/dL) | 3.3–4.8 | |
| Aspartate transaminase (IU/L) | 24 | 0–40 |
| Alanine transaminase (IU/L) | 15 | 0–40 |
| Alkaline phosphatase (IU/L) | 82 | 30–115 |
| Total bilirubin (mg/dL) | 0.2–1.3 | |
| Direct bilirubin (mg/dL) | 0.1 | 0.0–0.2 |
| Haptoglobin (mg/dL) | 201 | 43–212 |
| Lactate dehydrogenase (mU/mL) | 163 | 100–225 |
| Creatine phosphokinase (IU/L) | 147 | 22–269 |
| Reticulocyte (%) | 1.64 | 0.85–2.50 |
| Iron (mcg/dL) | 37 | 35–140 |
| Vitamin B12 (pg/mL) | 558 | 211–911 |
| Folate (ng/mL) | 11.80 | 3.00–20.00 |
| Thyroid stimulating hormone (µIU/mL) | 0.64 | 0.55–4.78 |
| International normalized ratio | 1.2 | |
| Prothrombin time (s) | 15.0 | 12.0–14.4 |
| Activated partial thromboplastic time (s) | 35.3 | 23.9–36.5 |
| Lactic acid (mEq/L) | 1.2 | 0.5–2.2 |