FAST FISH is not simply “conventional FISH with the overnight incubation shortened”. Validated rapid systems use probe chemistry, hybridisation buffer and workflow conditions designed to achieve useful signal in roughly 1–3 hours. Conventional workflows often hybridise overnight. Use FAST FISH only when the specific probe, specimen and protocol support it.
Hybridisation time is one of the biggest contributors to fluorescence in situ hybridisation turnaround time. Conventional FISH has traditionally relied on overnight incubation, whereas newer accelerated chemistries can reduce hybridisation to a few hours and enable same-day workflows in selected applications.
What is FAST FISH?
FAST FISH is a general term for FISH workflows engineered to reduce hybridisation time compared with conventional overnight methods. It is not one universal protocol. Commercial examples include Abbott's fast-working IntelliFISH chemistry, Agilent IQFISH and OGT/CytoCell FAST FISH products.
- Abbott publishes a 2–3 hour hybridisation condition for its fast-working FFPE chemistry, compared with 14–24 hours for its conventional LSI/WCP workflow in the same comparison document.
- Agilent states that its IQFISH hybridisation buffer supports genomic DNA probe hybridisation in 1–2 hours and can deliver complete manual FISH staining in about four hours for selected FFPE workflows.
- OGT/CytoCell describes validated 2-hour FAST FISH protocols for selected probe kits.
FAST FISH vs conventional FISH at a glance
| Feature | FAST FISH | Conventional FISH |
|---|---|---|
| Hybridisation | Typically around 1–3 hours where validated | Commonly overnight, often 14–24 hours depending on assay |
| Turnaround | Can support same-day result generation | Often spans into the next day |
| Probe chemistry | Requires a probe/buffer system validated for accelerated kinetics | Broad range of established commercial and laboratory workflows |
| Specimen compatibility | Probe- and specimen-specific | Also specimen-specific, but with a larger legacy protocol base |
| Method transfer | Cannot be assumed from an overnight protocol | Established method should still be locally validated |
| Best fit | Time-sensitive or high-throughput workflows where fast chemistry is supported | Routine workflows, legacy validations, probes without a validated rapid condition |
Why can rapid FISH work?
Hybridisation rate depends on probe concentration, probe length/design, target accessibility, buffer composition, temperature, viscosity and diffusion. Commercial accelerated systems modify one or more of these variables so that sufficient probe–target binding is reached earlier. That is why “FAST FISH” should be treated as a validated chemistry/workflow rather than merely a shorter timer.
When does FAST FISH make sense?
- When the target probe has a validated short-hybridisation protocol.
- When same-day workflow matters for throughput, scheduling or experimental turnaround.
- When the specimen type used in your laboratory is included in, or has been validated against, the accelerated method.
- When your laboratory can verify that signal intensity, background and scoring concordance remain acceptable.
When should you stay with a conventional overnight protocol?
- The probe manufacturer does not support a short-hybridisation condition.
- The specimen is difficult, poorly fixed or otherwise outside the validated rapid workflow.
- Signal is already marginal under the longer method.
- Your laboratory has a validated overnight method and there is no operational reason to change it.
- The intended use requires formal method verification/validation that has not yet been completed for a rapid protocol.
Can I convert any FISH probe to a 2-hour protocol?
No. The safest assumption is no unless the probe chemistry and workflow have supporting validation. Reducing a 14–24 hour hybridisation step to two hours can reduce signal or alter background if the probe/buffer system was not designed for the shorter incubation.
What should be compared during a FAST FISH validation?
- Signal intensity and signal-to-background ratio
- Normal and abnormal signal-pattern concordance
- Percentage of scorable nuclei/cells
- Nuclear/tissue morphology
- Background fluorescence and non-specific signal
- Failure/repeat rate
- Inter-observer agreement where manual scoring is used
- Run-to-run and lot-to-lot consistency
ABMIUM access to FISH probes
ABMIUM currently lists 444 active research-use FISH Probe Reagents from Wuhan HealthCare Biotechnology, within a broader FISH probe collection. The catalogue spans deletion, amplification, enumeration/centromeric, break-apart, fusion and locus-specific designs.
If your priority is a 2-hour hybridisation workflow, do not assume every catalogue entry has the same validated condition. Send us your target, specimen type and current workflow and we can confirm the relevant manufacturer-supported hybridisation conditions before you order.
FAST FISH FAQ
Is FAST FISH as accurate as conventional FISH?
A validated FAST FISH assay can produce comparable interpretable results, but accuracy and concordance must be demonstrated for the specific probe, specimen and scoring system. Abbott, Agilent and OGT/CytoCell all publish rapid systems with defined conditions rather than recommending arbitrary time reduction.
Does FAST FISH reduce the whole assay to two hours?
No. “Two-hour FISH” usually refers to hybridisation time. Pretreatment, denaturation, post-hybridisation washing, counterstaining and imaging still take additional time.
Is overnight FISH obsolete?
No. Overnight FISH remains appropriate for many validated assays and probes. Rapid workflows are an additional option, not a universal replacement.
Can FAST FISH be used on FFPE?
Yes for validated products/workflows. Abbott and Agilent both publish accelerated FFPE approaches. However, FFPE pretreatment remains critical and tissue fixation quality can still determine performance.
Related resources
- Fluorescence in situ hybridisation (FISH) protocol
- How to choose a FISH probe
- FISH troubleshooting guide
- FISH protocol: FFPE, cytology, hybridisation and analysis
- FISH probe selection guide
- FISH troubleshooting guide
- Browse FISH probes
References and technical sources
- Abbott Molecular — Vysis IntelliFISH Solution.
- Abbott Molecular — Fast-working vs conventional FFPE hybridisation conditions.
- Agilent — In Situ Hybridization / IQFISH overview.
- OGT/CytoCell — FAST FISH prenatal probe kit, 2-hour hybridisation.
- Huber D, Voith von Voithenberg L, Kaigala GV. FISH: history, limitations and micro-scale approaches. Micro and Nano Engineering. 2018.