Which branches make up a coagulation analyzer fluidic system?
Arrows indicate task relationships, not that every component is connected in series in one tube. Check valve positions, pump wetted boundaries and operating states for each branch.
The main branches handle plasma dispensing, reagent addition, probe washing and waste removal. Separate reagent probes, heated sections or dedicated channels depend on the assay mix, storage conditions and test cycle time.
Clot detection may identify clot formation optically or mechanically; chromogenic methods read color development and immunoturbidimetric methods read the turbidity change of the corresponding reaction. Optical detection requires attention to bubbles and liquid-surface effects on the optical path; mechanical clot detection still requires consistent dispensing, mixing and reaction conditions. Multiple detection modules in one instrument do not justify using the same trigger time for all assays.[1][2]
Common product roles and application guides
Configure components backward from the actual receiving location: establish probe-tip delivery first, then metering, routing, prewarming and cleaning. Heating and result interpretation are instrument functions that must be coordinated with pump and valve actions.
| Product | Task in a coagulation analyzer |
|---|---|
| Piston pump / syringe pump | Drive metered aspiration and dispensing of plasma and reagents, matching actual doses and auxiliary strokes |
| Liquid diaphragm pump | Supply liquid to clean inner and outer probe surfaces, accounting for wash-station resistance and simultaneous demand |
| Multiport rotary valves / solenoid valves | Select liquid sources and cleaning paths, control on/off states and coordinate metering and prewarming timing |
| Sampling and wash probes | Perform sampling and in-cuvette delivery, coordinated with positioning, cleaning and instrument thermal design |
| Bubble and pressure detection | Output abnormality signals that the instrument associates with dispensing steps and reaction cuvettes |
| Tubing and fittings | Connect sources to probe tips, controlling resistance, retained volume and assembly consistency |
Operating conditions to confirm at each stage
Draw one test as a timeline, marking aspiration, waiting, prewarming, dispensing, mixing and acquisition separately. Storage temperature, heater setpoint and liquid arrival temperature are different conditions.
| Stage | Conditions determining configuration |
|---|---|
| Plasma dispensing | Dose range, receiving position at the probe tip, whether sample enters the pump chamber, isolation interface |
| Reagent addition | Each reagent's dose and order, assay-specified arrival temperature and permissible addition window |
| Detection timing | Trigger event, mixing, preincubation and acquisition window for clotting, chromogenic or immunoturbidimetric assays |
| Path switching | Valve position, shared-segment volume, flushing consumption and first-dose recovery time after switching |
| Cleaning and monitoring | Inner/outer surface coverage, residual wash fluid and confirmable action status at alarm |
Sample delivery: control receiving position and residue
Small plasma doses require attention to droplets at the probe tip, liquid adhering to the cuvette wall and the system-liquid interface. Measure received volume using the actual cuvette and probe position, then assess whether the liquid reaches the reaction zone promptly. Faster dispensing may reduce hanging droplets but increase splashing and foam; choose the speed profile by end-point behavior.
With system-liquid drive, examine the isolation interface and sample dilution. With direct contact, include the pump chamber, valves and connectors in the cleaning path. Capacity must cover sample, isolation segments and necessary auxiliary actions while retaining useful stroke for routine small doses; resolve the large-capacity versus small-dose trade-off using probe-tip delivery data.
Reagent addition: use actual arrival as the timing reference
Use suitable development observations to establish the timing between the control signal, liquid leaving the probe, contact with liquid in the cuvette and completion of dispensing. For clotting assays, associate the initiation event with timing as defined by the method; for chromogenic and immunoturbidimetric assays, schedule acquisition by their incubation and reading rules. Completion of pump-motor movement is only one control event.
The method determines whether and where reagents are prewarmed and the permitted temperature at arrival. Longer heating residence may bring temperature closer to target but changes cycle time and reagent exposure. Short tubing reduces retained liquid and transfer distance, yet heat loss at the probe tip still needs checking. After changing probes, tubing length or aspiration/dispensing speed, review arrival temperature, delay and first-dose behavior together.
Further technical reading
Path switching: align valve positions with reaction timing
One metering unit with multiport routing can aspirate different liquids sequentially when flushing waits are acceptable. Dedicated paths reduce shared-segment flushing for residue-sensitive, frequently used or differently temperature-controlled reagents, at the cost of more metering and cleaning units.
Each valve position should have a defined source, destination and permitted action. Even after the valve reaches position, the shared segment may retain the previous liquid. Complete assay-required flushing and preparation before the dispensing that starts the reaction. Place valve switching, priming and the cuvette reaction on one timeline to identify the true throughput-limiting step.
Further technical reading
Cleaning: protect the next reaction's starting conditions
Treat internal residue, liquid on the probe exterior and residual wash fluid separately. Internal flushing addresses the wetted path; external washing covers immersed and splashed surfaces; post-cleaning drainage or recovery affects the next dose's concentration and volume. If extra wash fluid solves a local issue, also evaluate waste load and water remaining for the next dose.
Check residue effects in the assay-switching sequence, especially the first dose after cleaning. If only the first dose is abnormal, first examine flushing, tip droplets and thermal state before changing recovery. Each extra pre-dispense consumes reagent and cycle time.
Further technical reading
State monitoring: identify affected reaction cuvettes
Bubble and pressure sensors provide fluidic-state signals; the instrument control system associates cuvette number, assay and dispensing step. Alarm records should retain event time, valve position, commanded volume, action completion and actual volume only when independently measured. Sending a dispensing command alone cannot confirm the volume received in the cuvette.
Use different handling rules for abnormalities before and after reaction initiation. During recovery, first establish the cuvette's stage, then decide under the method whether to continue, discard or repeat. After partial dispensing with unknown actual volume, do not simply resend the full dose to the same cuvette.
Explore configurations through product application guides
FOREACH HMD combines glass syringes with solenoid valves and can be compared for single or multiple metering channels. HLD combines a glass syringe with a multiport rotary valve for sequential routing with one metering unit. Focus on the number of metering units needed, replenishment timing and shared wetted segments, not port count alone.[3][4]
Compare piston and syringe pumps by dose, auxiliary strokes and aspiration/dispensing speed; configure cleaning pumps around actual supply and first-dose recovery. Coordinate probes and tubing with receiving position, retained volume and thermal structure, and place sensors according to the phase of the abnormality. Once a model is selected, check the design against its capacity, materials and operating-point data.
- View the IVD product–task matrix
- Piston pumps in coagulation analyzers
- Syringe pumps in coagulation analyzers
- Diaphragm pumps in coagulation analyzers
- Multiport rotary valves in coagulation analyzers
- Sampling probes in coagulation analyzers
- Bubble and pressure sensing in coagulation analyzers
- Tubing and fittings in coagulation analyzers
Validate the complete cycle through application results
Check both delivery and assay results using the same actual cuvettes, probes, tubing and reagents. Cover routine continuous operation, standby recovery, liquid changes and the first dose after cleaning separately.
| Stage | Actual measurement | Priority areas to investigate |
|---|---|---|
| Plasma delivery | Volume received in the cuvette, residual droplets and between-sample carryover | Air aspiration, hanging tip droplets, cuvette-wall adhesion and isolation interface |
| Reagents and timing | Added volume, arrival time and variability, arrival temperature and complete reaction | Trigger mapping, mixing, temperature control and speed sequence |
| Path switching | Residue after flushing, first-dose volume and preparation time | Liquid retained in shared segments, valve position and flushing sequence |
| Cleaning recovery | First-dose concentration or volume, assay results and liquid use | Inner/outer coverage, residual water and thermal state |
| Abnormality identification | Phase-specific detection, false alarms, response and cuvette-number association | Signal location, event time and control state |
Common selection and recovery questions
Can completion of pump movement directly define the start of clotting?
First measure the relationship between the pump signal, liquid leaving the probe and contact in the cuvette, then define the start according to the method. A stable control offset can be included in instrument timing; excessive variability calls for addressing bubbles, hanging droplets, the path or drive first.
Does faster dispensing shorten the test cycle?
Only if actual dispensing, mixing, temperature and method-specific waiting requirements are all met. First locate the bottleneck in aspiration, prewarming, flushing or the detection window. If the method fixes the wait, shortening motor motion alone may not increase actual throughput.