What laboratory tests should be ordered for a 67-year-old postmenopausal woman presenting with right-sided pain?

Laboratory Tests for Right-Sided Pain in a 67-Year-Old Postmenopausal Woman

For a 67-year-old postmenopausal woman with right-sided pain, a comprehensive laboratory workup should include complete blood count (CBC), comprehensive metabolic panel (CMP), urinalysis, and inflammatory markers, followed by imaging studies to identify the underlying cause. 1, 2

Initial Laboratory Evaluation

First-line Laboratory Tests

• Complete Blood Count (CBC)

  • Evaluates for infection, inflammation, or anemia
  • Elevated white blood cell count may suggest infection or inflammation
  • Anemia may indicate malignancy or chronic disease

• Comprehensive Metabolic Panel (CMP)

  • Assesses liver and kidney function
  • Electrolyte abnormalities
  • Glucose levels

• Urinalysis

  • Rules out urinary tract infection
  • Evaluates for hematuria (possible kidney stone or malignancy)
  • Checks for pyuria (infection)

• Inflammatory Markers

  • C-reactive protein (CRP)
  • Erythrocyte sedimentation rate (ESR)
  • Helps distinguish inflammatory from non-inflammatory conditions

Second-line Laboratory Tests

• CA-125

  • Consider if ovarian pathology is suspected
  • May be elevated with ovarian malignancy, but has limited specificity

• Thyroid Function Tests

  • If symptoms suggest thyroid dysfunction

Diagnostic Approach Based on Location and Characteristics

Right Upper Quadrant Pain

• Liver Function Tests (LFTs)

  • AST, ALT, alkaline phosphatase, bilirubin
  • Evaluates for hepatobiliary disease

• Lipase and Amylase

  • Rules out pancreatitis

Right Lower Quadrant Pain

• Fecal Occult Blood Test
  • Screens for gastrointestinal bleeding
  • May indicate colorectal pathology

Imaging Considerations

The American College of Radiology recommends specific imaging studies based on laboratory findings:

• Pelvic Ultrasound (Transvaginal and Transabdominal)

  • First-line imaging modality for gynecologic causes 1
  • Evaluates for ovarian cysts, masses, or torsion
  • Assesses uterine pathology (fibroids, pyometra)

• CT Abdomen and Pelvis with IV Contrast

  • Recommended when ultrasound is normal or inconclusive 1, 2
  • Higher sensitivity (89% vs 70%) than ultrasound for urgent diagnoses
  • Evaluates both gynecologic and non-gynecologic causes

Common Etiologies in Postmenopausal Women

Gynecologic Causes

• Ovarian cysts (33% of cases) 1
• Uterine fibroids (second most common) 1
• Pelvic inflammatory disease (20% of cases) 1
• Ovarian neoplasms (8% of cases) 1
• Pyometra (rare but important consideration) 3
• Ovarian torsion (uncommon but serious) 4

Non-Gynecologic Causes

• Diverticulitis
• Appendicitis
• Bowel obstruction
• Colorectal malignancy
• Urinary tract conditions

Important Clinical Pitfalls

1. Assuming gynecologic origin

   • Up to 30% of patients with normal ultrasound may have abnormal findings on CT requiring intervention 2

2. Missing ovarian torsion

   • Often overlooked in postmenopausal women
   • Higher risk of malignancy in this age group 4

3. Overlooking pyometra

   • Can present with nonspecific abdominal pain without classic vaginal discharge 3
   • Risk factors include gynecologic malignancy and postmenopausal status

4. Delaying diagnosis

   • Delayed diagnosis in postmenopausal women can increase morbidity due to higher likelihood of malignancy 4

Follow-up Testing

Based on initial laboratory and imaging results, consider:

• Endometrial biopsy if uterine abnormalities are found
• CA-125, HE4, Risk of Malignancy Index if adnexal mass is identified
• Colonoscopy if gastrointestinal pathology is suspected

Remember that right-sided pain in postmenopausal women requires thorough evaluation as the differential diagnosis is broad and includes potentially serious conditions that may require urgent intervention.