Hemalite 1270: results differ on reruns of the same sample
What happened
A hematology analyzer gave different results on all main parameters (Hgb, WBC, RBC, PLT) each time the same sample was rerun, and multiple rinse cycles did not stabilise the readings. No error codes were reported in the case.
What was checked
- Several rinse cycles were run — the results stayed inconsistent.
- The engineers suspected air being drawn into the dosing system, most often at the pumps, less often at valves or tubing.
- On inspection of the syringe pumps, a dried residue trace was found on one of them.
Cause
Probable cause in this case: worn rubber seals on a syringe pump let air into the dosing system, so the blood was diluted with diluent in the wrong ratio and every parameter shifted from run to run.
The cause is probable and was not fully confirmed.
What was done
Disassemble the affected pump, clean and lubricate the rubber seals with inorganic grease, or fit new seals. The engineers noted this as the probable fix, not a confirmed one, so control material should be rerun afterwards to verify stable results before returning the analyzer to use.
Safety
The fluid path of a hematology analyzer carries patient blood residue: wear gloves and eye protection, and decontaminate the work area and removed parts before and after the repair.
Lesson: When every parameter drifts on reruns of the same sample, suspect the dilution path first — a worn pump seal with a visible dried residue trace is a classic air-ingress suspect.
Covered in the course: Lab Analyser Service — Level 2: Fault-Finding →
Written from an anonymised case shared by service engineers. It is not a manufacturer instruction and grants no authorisation. Independent note; names are trademarks of their owners.