For a patient presenting with suspected bacterial pneumonia in primary care, the recommended diagnostic approach primarily relies on clinical assessment supported by selective use of point-of-care tests rather than routine microbiological or imaging investigations initially.
Clinical diagnosis is based on symptoms and signs of lower respiratory tract infection, such as cough, sputum production, breathlessness, fever, and focal chest signs, in the absence of alternative explanations NICE CG191.
Risk assessment using the CRB65 score is advised to stratify severity and guide management decisions, including the need for hospital referral NICE CG191,NICE NG237.
Point-of-care C-reactive protein (CRP) testing can be used to support antibiotic prescribing decisions when it is unclear if antibiotics are needed. Specifically, immediate antibiotics are recommended if CRP is >100 mg/L, a back-up prescription considered if CRP is 20–100 mg/L, and antibiotics withheld if CRP is <20 mg/L NICE NG237.
Microbiological testing such as rapid point-of-care bacterial or viral tests, including influenza tests, is not routinely recommended in primary care to guide antibiotic prescribing but may be used for surveillance or infection control purposes NICE NG237.
Chest X-ray is not routinely performed in primary care to confirm diagnosis but is recommended if symptoms persist despite treatment, if there is suspicion of complications or underlying malignancy, or if the patient is at higher risk (e.g., smokers, age >50 years) NICE CG191,NICE CKS.
Recent literature highlights that while point-of-care tests for respiratory pathogens have potential benefits, their routine use in primary care is limited by variable accuracy and unclear impact on clinical outcomes, supporting current guideline recommendations to rely on clinical assessment and CRP testing primarily Nairz & Weiss 2025.
In summary, the diagnostic tests recommended in primary care for suspected bacterial pneumonia are clinical evaluation, CRP point-of-care testing to guide antibiotic use, and selective use of chest X-ray and microbiological tests based on clinical judgement and patient risk factors NICE CG191,NICE NG237,NICE CKS Nairz & Weiss 2025.
Key References
- CG191 - Pneumonia in adults: diagnosis and management
- NG237 - Suspected acute respiratory infection in over 16s: assessment at first presentation and initial management
- CKS - Chest infections - adult
- (Eshwara et al., 2020): Community-acquired bacterial pneumonia in adults: An update.
- (Nairz and Weiss, 2025): How to identify respiratory pathogens in primary health care - a review on the benefits, prospects and pitfalls in using point of care tests.