Introduction to Diagnostics

Correctly diagnosing a patient is a crucial aspect of healthcare. An incorrect diagnosis can lead to misinformed care, resulting in dangerous health outcomes if unnecessary treatment is given or the correct treatment withheld.

Diagnostics are means to reach a diagnosis and determine the appropriateness of a treatment therapy. A diagnostic test is a type of procedure which determines the presence of disease, and is typically done after the reports of symptoms or other medical test results. They are not only used for medical professionals to detect a disease or illness, but also the degree of development. For example, doctors may need to know what stage a disease is at, how it is progressing and whether it is stable or in regression.

Healthcare providers depend on various tools to diagnose conditions and inform treatment choices, and diagnostic tests can come in a range of forms, such as biopsies, colonoscopies, CT scans, ECGs or MRIs. In vitro diagnostics (IVDs), the most common of these, are tests that are conducted on samples such as blood or tissue that have been taken from the human body. In vitro diagnostics in infection make it possible to identify causative organisms, and to perform antibiotic susceptibility testing to prescribe targeted treatments.

Antibiotic resistance presents a global health crisis, however there are multiple ways diagnostic testing can help with this challenge. Without diagnostic testing, healthcare workers would not know whether a patient is likely to benefit from a specific antibiotic and this may consequently result in antibiotic misuse.

Traditional medical practices included a number of steps to produce definitive results, however the emergence of rapid diagnostic tests (RDTs) have meant that results can now be returned within hours. Such rapid identification can help improve antimicrobial stewardship. For example, asymptomatic patients who are infected with resistant pathogens can be quickly identified, allowing for rapid isolation and reduced spread of drug-resistant bacteria throughout the healthcare facility.

In the case of NFGNB, accurate identification is crucial for correct patient management. In clinical microbiology laboratories, identifying NFGNB usually relies on phenotypic characteristics. More recently, molecular identification techniques have also begun emerging as another identification method. In the next step we will examine the different laboratory techniques used in their detection.