Microbiology laboratories across Low and Middle Income Countries (LMICs) operate under chronic budget ceilings, intermittent power, limited maintenance coverage, and constrained informatics pipelines that can delay clinician facing results and blunt clinical impact.1 Real world ICU experiences from tertiary centers further show that platform uptime, sample flow, and trained personnel determine whether advanced assays translate into actionable decisions, reinforcing that implementation architecture not technology alone drives outcomes.2

No single modality adequately addresses these constraints.

Culture remains indispensable for confirmation and phenotypic antimicrobial susceptibility testing, but slow time to result and post antibiotic false negativity limit its utility for early therapy optimization.2

Syndromic multiplex panels compress time to result from days to hours and cover common targets, yet they are bound to predefined menus multicenter evaluations of blood culture ID panels-report excellent on panel performance while highlighting clinically relevant off panel organisms that necessitate parallel/reflex culture.3

In respiratory care, panels can surface nucleic acids from colonizers or nonviable organisms: without semi quantitative interpretation and reflex steps, overtreatment becomes a real risk.4

Sequencing (targeted or metagenomic) extends breadth and helps in culture negative or atypical infections, but requires bioinformatics capability, contamination safeguards, and budget headroom making it best positioned as an escalation rather than universal front door in LMIC labs.5

These complementary strengths and weaknesses motivate a tri-layer diagnostic strategy: i) A rapid syndromic panel to rule in likely etiologies within hours. ii) Reflex culture as the specificity/AST anchor for confirmation and infection control actions and (iii) Targeted sequencing for unresolved, high suspicion scenarios.6

In sepsis pathways, embedding a blood culture ID panel within stewardship workflows has been associated with markedly shorter time to targeted therapy demonstrating how the first layer accelerates decisions while subsequent layers add depth and precision.7

ICU experience from Indian tertiary settings similarly shows that panel calls are most valuable when explicitly coupled to escalation de-escalation rules and confirmation by culture, underscoring that complement, not replace, culture.2

The clinical endpoints that matter in LMIC hospitals are concrete and trackable: diagnostic yield, time to effective therapy, days of broad-spectrum exposure, isolation days, length of stay, and readmissions.8

In emergency and ICU respiratory cohorts, panel guided management has reduced time to appropriate therapy and antibiotic exposure when tied to stewardship oversight, highlighting that rapid results must be embedded in governance to shift outcomes.9,10

ED focused evaluations likewise show pneumonia panels can accelerate actionable decisions but require reflex culture and clinical context to arbitrate colonization versus disease.11

In gastrointestinal pathways, selective reflex culture after panel positives improves specificity and infection control value while avoiding blanket culture of all specimens, with modelled reductions in technologist time and total costs critical signals for budget limited labs.12,13

Conversely, pediatric LMIC analyses caution that indiscriminate panel use without indication criteria and audit loops can strain budgets, emphasizing the need for disciplined test utilization and KPI dashboards.14

This review targets microbiologists, infectious disease clinicians, and administrators in tertiary and district LMIC hospitals, with emphasis on ED/ICU where decisions are time critical and stewardship consequences largest.

Contribution We synthesize a) Modality specific strengths and pitfalls, b) Reflex rules that operationalize a tri-layer algorithm, and c) A pragmatic implementation playbook (people, process, platform) including LIS prompts and audit cadence.

We also propose a concise set of KPI hooks time to effective therapy, DOT reduction, isolation days saved, and LOS/readmissions so programs can quantify impact and iterate locally under LMIC constraints.12,15

Syndromic multiplex assays (respiratory, gastrointestinal, blood culture ID, and CSF/meningitis panels) compress the diagnostic timeline from days to hours, enabling organism level signals during the first decision window of care.7,16 In emergency and ICU cohorts with suspected respiratory infection, panel enabled stewardship has been associated with faster time to appropriate therapy and reduced unnecessary broad spectrum exposure when results are embedded in governance pathways rather than used in isolation.9

Technically, these platforms contribute three pragmatic advantages. Speed: closed, cartridge style workflows deliver same shift outputs for high acuity patients.7 Breadth: curated, syndrome matched target menus often increase early etiologic yield relative to single target methods.17 Operational simplicity: standardized, low hands on steps are valuable where staffing is thin and shift variability is high.17 Semi quantitative binning on some respiratory panels further supports clinical correlation by down weighting low level colonizers when pre-test probability is modest.

These gains, however, come with predictable traps if panels are applied uncritically. Target menu limitation: clinically important off panel organisms will be missed even when the assay performs excellently on panelled targets necessitating parallel or reflex culture.16 Colonization vs. infection: nucleic acids from airway commensals or nonviable organisms may inflate positive calls: without semi quantitative interpretation and clinical context, overtreatment is likely.18 Co detections multiple hits are common in respiratory and GI pathways and can distort perceived complexity unless adjudicated with host factors, imaging, and biomarkers.17 Resistance inference limits: although some panels-report key resistance genes, stewardship decisions generally still require phenotypic susceptibility testing reinforcing the need to complement (not replace) the panel layer with culture.16

Accordingly, interpretation anchors should be explicit in routine use. i) Pre-test probability (syndrome severity, host factors, and imaging). ii) Sample quality and site, and iii) Infection control context (will the result change isolation or source control In respiratory and gastrointestinal workflows, structured reflex culture after panel positives restores specificity, enables phenotypic AST, and supports outbreak/infection control actions two pragmatic frameworks describe selective (not universal) culture triggers.12,15 Programs in resource limited settings should also codify utilization rules (indications, repeat testing boundaries, and actions on low bin results) and maintain an audit cadence, because indiscriminate testing can strain budgets without improving outcomes.13 Bottom line: panels are powerful rule in accelerators, but they deliver safe, stewardship aligned value only inside a tri-layer workflow where reflex culture and, when necessary, targeted sequencing provides specificity and resistance resolution.7,12

Reflex culture remains the cornerstone for adjudicating true infection versus colonization and for delivering phenotypic Antimicrobial Susceptibility Testing (AST) capabilities that no rapid panel can fully replace.16 In routine workflows, panel positive results should trigger targeted culture of the same specimen (or an anatomically appropriate companion specimen) to confirm organism identity, quantify growth, and generate AST within reporting windows that support de-escalation rather than merely documenting resistance late in the course.12,15 This panel culture handshake restores clinical specificity when multiplex assays detect nucleic acids from nonviable or colonizing organisms, a known source of overtreatment in respiratory and gastrointestinal pathways.19

Operationally, reflex culture adds three elements that convert an early molecular signal into a safe, stewardship aligned decision. First, organism confirmation with burden context: culture growth (including semi quantitative reporting or colony counts where relevant) helps discriminate pathogen from bystander, particularly when panels-report low bin or borderline detections.15,20 Second, phenotypic AST: while select panels carry resistance gene calls, actionable narrowing typically hinges on MIC based or disk diffusion data reflex culture supplies this within a defined window so that clinicians can de-escalate before day 3‒4.12 Third, infection control signal quality: culture enables strain level or phenotype linked alerts (e.g., ESBL, MRSA, carbapenemase phenotypes) that drive isolation and cohorting decisions, often more reliably than gene surrogates alone.21

Reflex rules should be disease and target specific rather than universal. For bloodstream infection pathways, any panel detected pathogen or resistance determinant that would change therapy or isolation merits immediate subculture from the blood culture bottle, plus directed plates for fastidious organisms contamination controls (e.g., single bottle coagulase negative staphylococci) should be codified to avoid unnecessary workups.22 In respiratory syndromes, laboratories should culture panel positive lower respiratory specimens when semi quant bins are moderate/high or when clinical severity is high for low bin detections in low pre-test settings, selective culture paired with clinical correlation curbs overtreatment and unnecessary AST.23 For gastrointestinal panels, selective reflex culture of bacterial positives (e.g., Salmonella/Shigella/Campylobacter) enables susceptibility reporting and public health flags without reverting to blanket culture of all stools this approach has demonstrated reductions in technologist time and overall costs when implemented with rules.12

Turnaround Time (TAT) discipline is central. Molecular positives should be released rapidly with an embedded comment that reflex culture is in progress and that definitive AST will follow by a specified deadline, aligning clinicians’ expectations with laboratory kinetics.15 Many programs have standardized “rapid phone out” for critical targets (e.g., S. aureus in blood, N. meningitidis in CSF) simultaneous with setting up reflex culture, ensuring early source control while preserving the pathway to phenotypic confirmation.24 In LMIC settings, LIS prompts and rule based order sets reduce missed reflexes during busy shifts and mitigate variability across staff with differing experience levels.15

From a cost utility perspective, reflex culture is not a luxury it is the specificity and stewardship engine that protects panel investments. Modelling work shows that selective reflex strategies (rather than universal culture) can lower total laboratory costs and hands on time while preserving clinical utility an important balance where budgets are fixed and technologist capacity is limited.12,13 The practical message for LMIC hospitals is to deploy reflex culture with disciplined triggers, clear contamination rules, and defined reporting windows so that phenotypic data land early enough to change management.25

High-cost diagnostics in bloodstream infection, pneumonia, gastrointestinal disease and CNS infection only deliver net benefit when they are tightly coupled to antimicrobial stewardship (AMS) rather than used as stand-alone technologies. A 2024 network meta-analysis of 88 studies in bloodstream infections showed that Rapid Diagnostic Tests (RDTs) improved survival only when combined with an active AMS programme, with RDT + AMS outperforming both conventional blood culture alone and blood culture + AMS for mortality and time to optimal therapy.43 Evidence hierarchy and interpretation note: The most reproducible gains in the RDT literature come from implementations where the test is paired with an explicit stewardship “action loop” rather than deployed as a stand-alone technology. However, much of the impact evidence (including BCID2 and pneumonia panel rollouts) is quasi-experimental (pre–post and observational), and effect sizes can be inflated by co-interventions that often arrive at the same time (updated empiric guidelines, new order sets, audit-feedback cadence, staffing changes). For this reason, reported reductions in time to optimal therapy or broad-spectrum exposure should be read primarily as the impact of a bundled pathway redesign (“test + workflow + AMS response”), with expected attenuation in settings where stewardship bandwidth is limited.

In sepsis/BSI, multiple BCID2 implementation studies have demonstrated substantial reductions (often >24‒30 h) in time from empirical therapy to optimal, targeted therapy when BCID2 results automatically trigger AMS review, compared with MALDI-TOF or conventional methods alone.44,45 Cost effectiveness analyses suggest that cartridge and platform costs are offset by lower broad spectrum days of therapy, shorter ICU/hospital stay and fewer downstream investigations when AMS consistently acts on RDT outputs.46

For pneumonia, real world evaluations of the BioFire Pneumonia Panel in ICUs show that semi quantitative results integrated with stewardship review facilitate early de-escalation or discontinuation of unnecessary antibiotics in a meaningful proportion of patients, while avoiding unsafe narrowing in high risk hosts.47,48 Similar principles apply to gastrointestinal panels: clinical decision support tools embedded in the EMR have reduced overall GI-panel ordering and significantly lowered inappropriate tests (e.g., laxative associated, no documented diarrhoea), highlighting that diagnostic stewardship is essential to justify panel cost and prevent overtreatment of colonising or self-limited pathogens.35,49

For metagenomic sequencing, recent cohorts and reviews across sepsis, respiratory and CNS infections show that mNGS increases diagnostic yield and prompts management changes in roughly 20%‒40% of tested patients, particularly when used selectively in culture negative, high suspicion cases.41,50,51 While some tertiary-centre series report shorter treatment duration and lower total episode costs compared with prolonged empirical management, these economic signals are highly context-dependent and may not translate directly to LMIC hospitals where costing structures, bed-day valuation and downstream capacity differ. LMIC programmes should therefore treat cost offsets as uncertain and prioritise local budget-impact evaluation before expansion beyond strict reflex indications.

Collectively, these data imply that the hybrid tiered algorithms proposed in this review are only sustainable if laboratories and AMS teams co-design: i) Strict indication criteria and order sets for panels and sequencing, ii) Automatic AMS notification for high impact results, and iii) Routine audit of time to targeted therapy, broad spectrum DOT and cost per additional actionable diagnosis. Minimum stewardship capacity (pragmatic baseline for LMIC sites): For tiered pathways to translate rapid results into safer antibiotic decisions, programmes should define a minimum operating set: i) A named AMS focal person or small rota accountable for acting on high-impact calls (sepsis/ICU), ii) A rapid communication channel for time-critical results (phone/secure message/LIS alert) with a clear escalation pathway, iii) Syndrome-linked empiric and de-escalation rules anchored to the local antibiogram, and iv) A simple daily review touchpoint (even once per working day) for sepsis/ICU RDT outputs. Where this action loop is absent, rapid panels can increase organism detection without improving outcomes and may unintentionally increase antibiotic exposure through ungoverned responses to positive signals. LMIC-facing cost-utility framing (pragmatic and measurable): Because many LMIC hospitals operate under hard budget constraints, cost-utility should be expressed not only as “cost-effectiveness” but also as budget impact and affordability under realistic volumes. A practical approach is to report i) Direct programme cost per test episode (cartridge/reagents, QC/controls, labour time, maintenance, and basic IT/LIS support), ii) Actionability rate (proportion of tests that trigger a stewardship or IPC action), and iii) Downstream offsets that are plausibly attributable to governed use (broad-spectrum DOT avoided, avoidable repeat diagnostics, isolation days optimised, and length-of-stay change where credible). Importantly, savings may manifest as released capacity rather than cash savings; therefore, reporting should explicitly distinguish “financial savings” from “capacity gains” and avoid assuming that reduced LOS automatically converts to budget return in all LMIC settings.

Translating hybrid diagnostic algorithms into routine practice is constrained first by laboratory level barriers. A recent JAC perspective on rapid ID/AST technologies highlights high capital and per test costs, limited reimbursement, need for 24/7 skilled staff, IT integration, and the complexity of redesigning workflows as major reasons why many laboratories cannot insource rapid systems despite clear clinical benefits.52 An ASM Laboratory Practices Subcommittee report further emphasises that diagnostic stewardship responsibilities are being added to laboratories already facing workforce shortages and fragile infrastructure, making sustained implementation difficult without institutional investment and protected time.53 Workforce and competency (task-shifting without losing governance): Because LMIC laboratories often cannot staff 24/7 specialist microbiology coverage, a tiered workforce model is more realistic than an “expert-only” model. Core tasks can be distributed with clear boundaries: technologists execute standardized workflows (panel run, reflex culture set-up, critical value phone-out templates); a supervising microbiologist validates complex/discordant outputs and maintains QC; and an AMS liaison (medicine/pharmacy) converts high-impact results into time-bound treatment actions using agreed de-escalation rules. For sites without an on-site ID physician, a small rota of trained internal medicine/ICU clinicians supported by pharmacy can function as the AMS action loop, provided there is a documented escalation pathway for complex cases. Competency should be operationalized as short, auditable modules (sample quality checks, semi-quant interpretation, contamination control, reflex triggers, and report wording), with quarterly refreshers and a “second-reader” rule for high-stakes results (sepsis/CSF, IPC organisms, sequencing reports).

In Low and Middle Income Countries (LMICs), these barriers are multiplied by limited access to basic microbiology, unreliable power and cold chain, and the near absence of formal stewardship programmes in many hospitals. Narrative reviews and qualitative work from LMIC settings describe under resourced laboratories, fragmented supply chains and weak governance as key obstacles to embedding microbiology driven stewardship, even before high-cost molecular platforms are considered. Under these conditions, the immediate priority is often to secure reliable culture, AST and basic quality systems, and to link them to pragmatic AMS rather than to deploy broad panels or mNGS at scale.54 Sustainability (what keeps the pathway alive after launch): Hybrid diagnostics fail most commonly during the “maintenance phase” when cartridges, controls, culture media, or staffing continuity break down. Programmes should therefore define a minimum sustainability package at launch: i) Protected time for at least one laboratory and one AMS lead to own SOPs and audit, ii) A small buffer stock policy for critical consumables and controls, iii) Basic downtime procedures (manual phone-out, paper reflex triggers) for power/LIS interruptions, and iv) Simple retention levers such as cross-training, clear role recognition (e.g., “RDT steward”), and documented escalation support from a tertiary/reference mentor site. These measures do not require high capital investment but materially reduce attrition of performance after the initial implementation period.

For metagenomic sequencing, multiple contemporary reviews converge on a similar set of translational challenges: high per sample cost, lack of standardised wet lab and bioinformatic pipelines, variable analytical sensitivity across specimen types, and difficulty distinguishing clinically meaningful reads from background contamination or commensal flora.55,56 A 2025 Diagnostics review adds regulatory uncertainty, absence of harmonised reporting standards and unresolved reimbursement models especially in resource constrained settings to this list.57 Ethical and data governance concerns about human genomic information generated alongside pathogen reads also complicate routine deployment.58

Beyond analytical constraints, two practical levers can improve the actionability of advanced diagnostics in LMIC hospitals: i) Triage-driven prioritisation of high-cost testing using simple sepsis screening approaches built from routinely available parameters (e.g., lymphocyte count, INR and procalcitonin), and ii) Explicit linkage of empiric/de-escalation pathways to population-specific epidemiology for example, a global synthesis in hematological malignancy cohorts summarizes the burden of E. coli bloodstream infection and associated resistance patterns that should be reflected in local guidance.59,60 In parallel, outcome studies in carbapenem-resistant Gram-negative infections show clinically meaningful differences between active regimens (e.g., ceftazidime-avibactam-based therapy versus polymyxin-based approaches), reinforcing the importance of timely optimisation of effective treatment.61,62

At the health system level, hybrid algorithms demand tight integration of diagnostic and antimicrobial stewardship. International frameworks now describe diagnostic stewardship as a formal continuum of AMS, requiring governance structures, agreed test ordering rules, and shared metrics rather than ad hoc local efforts. However, comparative effectiveness and cost utility data for different implementation models (centralised versus decentralised testing, hub-and-spoke sequencing services, or restricted indication order sets) remain limited, particularly in LMICs.

Pragmatic delivery model for sequencing (recommended for many LMIC systems): A hub-and-spoke approach can make Tier 3 achievable without forcing every hospital to insource sequencing. Spoke sites (district/secondary hospitals) define strict reflex criteria, collect and store specimens using a simple pre-analytical checklist, and ensure that Tier 2 culture/AST continues in parallel. The hub (tertiary/reference laboratory) runs validated wet-lab and bioinformatic pipelines, tracks contamination/QC metrics, and returns a report that is explicitly “action-oriented” (confidence level, likely pathogen versus background, and suggested confirmatory steps). Crucially, the service agreement should define realistic turnaround targets and an escalation pathway for time-critical ICU cases; otherwise, delayed sequencing risks becoming academically interesting but clinically irrelevant.

Key research gaps include: robust cost effectiveness studies of tiered algorithms in diverse settings prospective trials of diagnostic stewardship interventions specifically tailored to multiplex panels and mNGS development of simplified, quality assured mNGS workflows suitable for regional reference laboratories and models for workforce training and retention in microbiology and bioinformatics. Addressing these gaps will determine whether the proposed hybrid strategies can move from tertiary academic exemplars to scalable, equitable tools for global infectious disease care.

Practical note: “Accountable Role” in Table 1 is intentionally framed as a small cross-functional loop (laboratory + AMS + IPC), so that sites can implement the pathway through role-mapping and task-sharing rather than relying on a single specialist individual.

Table 1 operationalises Fig. 1 by mapping each tier and trigger to mandated actions, service-level targets and accountable roles (lab + AMS + IPC).

Fig. 1.

Syndrome-wise three-tier hybrid diagnostic algorithms.

Current evidence supporting hybrid tiered algorithms is dominated by single-centre studies and high-income tertiary hospitals, many of which already have reliable culture/AST, continuous staffing, and mature stewardship infrastructure. Data from low- and middle-income countries remain limited, so generalisability to laboratories facing personnel constraints, intermittent supplies, and minimal IT support is uncertain. The impact literature is also largely quasi-experimental, with heterogeneous endpoints and outcomes that are strongly mediated by stewardship intensity and co-interventions introduced during roll-out, this makes it difficult to isolate the independent contribution of any single modality (panel versus workflow versus AMS response). LMIC-specific cost-effectiveness analyses are sparse, particularly for sequencing, where per-sample cost, quality controls, bioinformatics, governance, and regulatory requirements can be prohibitive outside reference-laboratory models. Future work should prioritise pragmatic multicentre evaluations in LMIC health systems, compare delivery models (in-house versus hub-and-spoke), and report a consistent outcome set (time to effective therapy, broad-spectrum DOT, LOS, and cost per actionable diagnosis) alongside implementation measures (workforce time, supply resilience, and quality indicators).

This review argues that modern microbiology is most effective when organised as a disciplined, three-tier hybrid pathway rather than as a loose collection of tests. At Tier 1, syndrome-specific rapid panels for sepsis, pneumonia, gastrointestinal infection, and CNS disease buy time: they move the team quickly from “any bug” to a short list of plausible pathogens and resistance markers, but they are deliberately not treated as stand-alone answers. Tier 2 reflex culture with targeted adjunct tests remains the non-negotiable specificity anchor, confirming viability, distinguishing infection from contamination or colonisation, providing phenotypic susceptibility data and supplying isolates for infection prevention and public health. Tier 3, targeted or metagenomic sequencing, is reserved for the small but clinically critical subset of high suspicion, culture negative cases where additional breadth can genuinely change management. Across all four syndromes, the message is the same: benefit comes not from technology alone but from how it is embedded. Clear indications, explicit reflex rules, tight linkage to antimicrobial stewardship and routine audit of key performance indicators are what convert panels, culture and sequencing into a coherent, accountable diagnostic service that can be adapted to both resource rich and resource limited settings.

The authors used AI language models (such as ChatGPT, OpenAI) only to refine language and improve clarity. All content has been reviewed and approved by the authors, who take full responsibility for the final manuscript.

None.

The data that support the findings of this study are available from the corresponding author upon reasonable request.