Recommended Tests and Treatments for Suspected Malaria
Malaria should be diagnosed using thick and thin blood films combined with rapid diagnostic tests (RDTs), and treatment should be based on Plasmodium species identification, severity assessment, and regional resistance patterns. 1
Diagnostic Testing
Initial Evaluation
- Travel history: Obtain detailed geographical history, time of onset and duration of symptoms 1
Required Laboratory Tests
Blood films and RDTs:
- Thick and thin blood films processed from EDTA sample are the mainstay of diagnosis 1
- Perform RDTs in all patients who have visited a tropical country within 1 year 1
- Three thick films/RDTs over 72 hours should be performed to exclude malaria with confidence 1
- Positive blood films should be sent to reference laboratory for confirmation 1
Additional tests:
- Complete blood count (CBC): Look for thrombocytopenia, lymphopenia, eosinophilia 1
- Blood cultures: Take two sets prior to antibiotic therapy 1
- Renal and liver function tests 1
- Serum save for additional testing if needed 1
- Urinalysis: Check for proteinuria, hematuria, hemoglobinuria 1
- Blood glucose: Hypoglycemia is a common complication 1, 2
Severity Assessment
High Risk (Immediate Risk of Death)
- Depressed consciousness (any degree)
- Active seizure activity
- Respiratory distress or hypoxia (O₂ saturation <95%)
- Shock (systolic BP <80 mmHg or <70 mmHg in children <1 year)
- Hypoglycemia (<3 mmol/L)
- Metabolic acidosis (base deficit >8 mmol/L)
- Severe hyperkalaemia (potassium >5.5 mmol/L) 1
Intermediate Risk (Need for High Dependency Care)
- Hemoglobin <100 g/L
- History of convulsions during current illness
- Hyperparasitemia >5%
- Visible jaundice
- P. falciparum in a patient with sickle cell disease 1
Treatment Recommendations
Severe Malaria (Any High-Risk Criteria)
- First-line treatment: Intravenous artesunate 1, 3
- Admit to intensive care unit
- Monitor parasitemia every 12 hours until decline (<1%), then every 24 hours until negative
- Monitor blood count, hepatic, kidney, and metabolic parameters daily 1
- Switch to oral therapy when parasitemia <1% and patient can tolerate oral medication 1
Uncomplicated P. falciparum Malaria
- First-line treatment: Oral artemisinin-based combination therapy (ACT) 1, 3
- Alternative options when ACT unavailable:
Non-falciparum Malaria (P. vivax, P. ovale, P. malariae, P. knowlesi)
- ACT or chloroquine (for chloroquine-sensitive infections) 3
- For P. vivax and P. ovale: Add primaquine or tafenoquine to eliminate liver hypnozoites and prevent relapse 1, 4
- G6PD testing required before starting primaquine/tafenoquine 4
Important Clinical Considerations
Common Pitfalls to Avoid
- Delayed diagnosis: Failure to expedite appropriate referral may lead to life-threatening disease 1
- Inadequate testing: Single negative blood film does not exclude malaria 1
- Overlooking severe malaria: Always assess for severity criteria 1
- Ignoring other diagnoses: In high transmission areas, presence of parasites doesn't exclude other causes of fever 5
- Inadequate monitoring: Patients with severe malaria require close monitoring for complications 1
Special Populations
- Children: Require weight-based dosing and have higher risk of severe disease 1
- Pregnant women: Higher risk of morbidity and mortality; treatment should be expedited 4
- Immunocompromised patients: May have atypical presentations 1
By following this algorithmic approach to diagnosis and treatment, clinicians can significantly reduce morbidity and mortality associated with malaria. Early diagnosis and appropriate species-specific treatment remain the cornerstones of effective malaria management.