Guidance

Diagnosis

Updated 17 June 2026

Suspected malaria is a medical emergency.

Consider malaria in every ill patient who has returned from the tropics in the previous year, especially in the previous 3 months.

Fever on return from the tropics should be considered to be malaria until proven otherwise.

Malaria cannot be diagnosed with certainty by clinical criteria alone. Suspected cases should be investigated by obtaining a blood film diagnosis as a matter of urgency.

There is no need to wait for fever spikes before taking blood; this only delays diagnosis and the fever pattern seldom conforms to text book periodicity, especially in the case of Plasmodium falciparum.

Blood tests and how to request them in the UK

A synopsis of blood tests and how to request them is given here. Full details are contained in the latest British Society for Haematology guidelines for the laboratory diagnosis of malaria, published in March 2022 (87).

Take an EDTA-anticoagulated venous blood sample.

The test request form should include the phrase ‘Urgent, suspected malaria’ and the form and the blood sample should be received in the laboratory within one hour of being taken as falciparum malaria may increase in severity over a few hours and the morphology of malaria parasites in EDTA deteriorates over time, rendering accurate laboratory diagnosis more difficult.

Finger-prick samples smeared directly onto microscope slides at the bedside are sub-optimal for modern diagnosis as the laboratory then has no additional material to make and stain further smears, undertake rapid diagnostic tests (RDTs) or refer for PCR testing.

Laboratories in England, Wales and Northern Ireland making a diagnosis of malaria should send blood films and a portion of the blood sample on which the diagnosis was made to the UKHSA Malaria Reference Laboratory (MRL). Laboratories in Scotland should refer to the Scottish Parasite Diagnostic Laboratory.

Rapid diagnostic tests (RDTs)

RDTs (sometimes known as ‘dipsticks’) can be used successfully by trained, selected high-risk groups (88) but the UK Malaria Expert Advisory Group (UKMEAG) does not recommend routine use of RDTs for self-diagnosis by travellers.

RDTs allow the detection of malaria parasites in human blood without microscopy. Used correctly, they can confirm the clinical diagnosis of malaria in places remote from medical attention (89). However, travellers may use them incorrectly and thus fail to detect parasites (90).

RDTs do have a place in the medical kit carried by a doctor or nurse accompanying an expedition to remote malarious regions. Performance of RDTs may be impaired if they are stored at temperatures outside the recommended range (91). Therefore, care must be taken to transport and store them correctly and thus prevent deterioration in their performance in the field.

Furthermore, a study of self-diagnosis by travellers and expatriates using RDTs which were available on the internet showed the RDTs used had variable diagnostic accuracy. Only 4 of 8 RDT products for self-diagnosis were judged reliable for the diagnosis of P. falciparum and P. vivax and none were reliable for P. ovale and P. malariae (92).

Appropriate choice of RDT product is therefore crucial and the WHO has an extensive product testing programme for RDTs. Prospective purchasers should consult the WHO web site for information to inform their decision.

Blood film and/or RDT negative malaria

One negative blood film or RDT does not exclude a diagnosis of malaria. RDTs are not a substitute for microscopy in UK practice, but have a useful role alongside blood films as additional tests.

Where malaria is suspected, blood films should be examined daily for 3 days while other diagnoses are also considered. If all these films are negative and malaria is still considered a possible diagnosis, expert advice should be sought from a specialist in tropical or infectious diseases. It is particularly important to seek such advice early in the care of pregnant patients with suspected malaria, as most parasites may be sequestered in the placenta such that peripheral blood films are negative despite the patient having malaria (see Information resources for expert advice listing).

Resources for treatment advice

The treatment of malaria is outside the scope of this document and is addressed in the UKMEAG malaria treatment guidelines.

Expert advice on malaria treatment may be obtained from:

• Hospital for Tropical Diseases
• Liverpool School of Tropical Medicine
• your local infectious diseases unit

Notification

Malaria is a statutorily notifiable disease and the clinician caring for the patient must complete a notification form (93).

In England, Northern Ireland, and Wales, the MRL reporting form should also be completed and sent to the MRL separately or along with referred specimens.

References

Numbers refer to the complete list of references found in the References attachment.

87. Rogers CL, Bain BJ, Garg M, Fernandes S, Mooney C, Chiodini PL, British Society for Haematology. ‘British Society for Haematology guidelines for the laboratory diagnosis of malaria’ British Journal of Haematology 2022: volume 197, issue 3, pages 271 to 282

88. Berthod D, Rochat J, Voumard R, Rochat L, Genton B, D’Acremont V. ‘Self-diagnosis of malaria by travellers: a cohort study on the use of malaria rapid diagnostic tests provided by a Swiss travel clinic’ Malaria Journal 2017: volume 16, issue 1, page 436

89. WHO. ‘The use of malaria rapid diagnostic tests (second edition)’ 2006

90. Jelinek T, Grobusch M, Nothdurft H. ‘Use of dipstick tests for the rapid diagnosis of malaria in non-immune travelers’ Journal of Travel Medicine 2000: volume 7, issue 4, pages 175 to 179

91. Chiodini PL, Bowers K, Jorgensen P, Barnwell JW, Grady KK, Luchavez J and others. ‘The heat stability of Plasmodium lactate dehydrogenase-based and histidine-rich protein 2-based malaria rapid diagnostic tests’ Transactions of the Royal Society of Tropical Medicine and Hygiene 2007: volume 101, issue 4, pages 331 to 337

92. Maltha J, Gillet P, Heutmekers M, Bottieau E, Van Gompel A, Jacobs J. ‘Self-diagnosis of malaria by travelers and expatriates: assessment of malaria rapid diagnostic tests available on the internet’ PLoS One 2013: volume 8, issue 1, article e53102

93. UKHSA. ‘Notifications of infectious diseases (NOIDs)’ (Notifications about suspected infectious diseases, collected by UKHSA)