Tarangnan Community HospitalClinical Laboratory	Document No.: WI-C-004-A-V0	CONTROLLED COPY Do not copy or remove
	Parent Document: SOP-C-004, Sections 5.2–5.7 \| Version: V0
Applies to: Medical Technologists \| Effective Date: MM-DD-YYYY \| Supersedes: None

Sensa Core ISE Electrolyte Analyzer Operation & Daily Cleaning Bench Card

Clinical Chemistry Section | Direct Potentiometric Serum Na+ / K+ / Cl- Protocol

STOP — CRITICAL SPECIMEN REJECTION RULES (PREVENT PSEUDOHYPERKALEMIA) NEVER USE: Lavender EDTA (K2/K3), Blue Citrate, or Gray Fluoride tubes — EDTA causes catastrophic false K+ > 15 mmol/L!
GROSS HEMOLYSIS: Reject visible pink/red serum (free Hgb > 100 mg/dL) — request urgent recollection immediately.
ACCEPTABLE: Plain Red-Top or Gold SST serum, or lithium-heparin plasma (green-top) per SOP-C-004; serum clotted 20–30 min upright, centrifuged at 1500–2000 × g, separated within 1–2 hours.

1
Reagent Pack & System Fluidic Check Inspect snap-in closed reagent module: verify Cal A and Cal B > 5% remaining; verify waste bag is NOT full (< 95% full). Check peristaltic pump tubing and verify Ag/AgCl reference line is primed without air bubbles. SOP-C-004, Section 5.3.1, 5.3.2
2
Two-Point Slope Calibration Verification Verify automated 2-point calibration (Calibrator A & B). Confirm electrode slopes: Na+ & K+: 50.0 to 62.0 mV/decade; Cl-: 40.0 to 58.0 mV/decade. If slope fails or is unstable, testing locks automatically; clean and recalibrate. SOP-C-004, Section 5.4.1
3
Daily Two-Level Quality Control (IQC) Run Analyze Level 1 (Normal) and Level 2 (Abnormal) aqueous/serum electrolyte controls every morning before patient samples. Apply Westgard rules — 1:2s = warning only (investigate); 1:3s / 2:2s / R:4s = reject: halt patient testing and troubleshoot. No patient results until QC passes. Document in Daily QC Logbook. SOP-C-004, Section 5.4.3
4
Stepwise Patient Sample Aspiration Ensure screen reads READY. Uncap unhemolyzed serum tube; present tube to the sample probe. Analyzer automatically aspirates 65 to 100 µL, withdraws probe, and displays Na+, K+, Cl- concentrations within 45–60 seconds. SOP-C-004, Section 5.5.1–5.5.7
45–60 s
5
Critical Value Verification & Telephone Protocol If result breaches critical limits (K+ < 2.8 or > 6.2; Na+ < 120 or > 160; Cl- < 80 or > 120 mmol/L): repeat run immediately to confirm; inspect tube; phone physician/ward within 15 min; require verbal read-back; log on F-QM-POST-002-A-V0. SOP-C-004, Section 5.6.1, 5.6.2
≤ 15 min
6
Daily End-of-Shift Pepsin Deproteinization Cleaning At end of shift, present Sensa Core Daily Cleaning Solution (pepsin deproteinizer) to sample probe. The proteolytic solution soaks the electrode chamber for exactly 3 minutes to remove serum proteins, followed by automated Cal A flush. SOP-C-004, Section 5.4.4
3 min soak
7
Weekly Sodium Electrode Conditioning Once weekly, aspirate dedicated Sodium Conditioning Solution (ammonium bifluoride) into the electrode chamber to revitalize the hydrated glass capillary membrane. Wear gloves and eye protection; see SDS — corrosive / fluoride source. Execute automated 2-point calibration immediately following conditioning. SOP-C-004, Section 5.4.5
WEEKLY

Electrode Slope Criteria & Reference Intervals

Electrode	Acceptable Slope	Adult Reference Interval
Sodium (Na+)	50.0 to 62.0 mV/decade	135 to 145 mmol/L
Potassium (K+)	50.0 to 62.0 mV/decade	3.5 to 5.1 mmol/L
Chloride (Cl-)	40.0 to 58.0 mV/decade	98 to 107 mmol/L

Critical Values (F-QM-POST-002-A-V0)

Electrode	Critical Low	Critical High
Sodium (Na+)	< 120 mmol/L	> 160 mmol/L
Potassium (K+)	< 2.8 mmol/L	> 6.2 mmol/L
Chloride (Cl-)	< 80 mmol/L	> 120 mmol/L

Action: Repeat run → Call ward within 15 min → Verbal read-back → Record on F-QM-POST-002-A-V0.

Prepared by: Chief Medical Technologist
Signature: _______________________ Date: ________

Reviewed by: Pathologist
Signature: _______________________ Date: ________

Approved by: Hospital Director
Signature: _______________________ Date: ________