Biochemistry Critical Results List: CPI-5.5.1.1.0.1


	Department of LMMD Division of Clinical Chemistry	CPI-5.5.1.1.0.1 Version: 2.29 Effective: 2024/10/11 E-Authorized by: Biochemist

Appendix 1: Table of Adult Critical Limits

Tests	Critical limits	Units
Acetaminophen	600 (4 hr. post ingestion) 400 (8 hr. post ingestion) 200 (12 hr. post ingestion & if ingestion time not available)	µmol/L
Ammonia	≥ 99	µmol/L
Bicarbonate	≤ 10 or ≥ 40 call the first critical result ≥40 call any critical result obtained 7 days or more from the first (a critical result on day 7 or more becomes the first critical result again)	mmol/L
Blood Gases Arterial pH pCO2 pO2 Bicarbonate Venous pH PCO2	≤ 7.20 or ≥ 7.60 ≤ 30 or ≥ 60 ≤ 60 ≤ 10 or ≥ 40 all results ≤ 10 are called call the first critical result ≥ 40 call any critical result obtained 7 days or more from the first (a critical result on day 7 or more becomes the first critical result again) ≤ 7.20 or ≥ 7.60 ≤ 25 or ≥ 60	mm Hg mm Hg mmol/L mm Hg
Calcium	≤ 1.50 or ≥ 3.00	mmol/L
Carbamazepine	≥ 63	µmol/L
COHb	≥ 0.150	F.T.Hb
Creatine Kinase	> 10,000 Out patient first result	IU/L
Creatinine (SB patients)	≥ 500 Call the first critical result ≥ 500 Do not call if within previous 2 months Creatinine has been ≥ 500 Do not call Dialysis patients	µmol/L
Creatinine (HC patients)	≥ 350	µmol/L
CSF Glucose	≤ 2.0	mmol/L
CSF Protein	≥ 1000	mg/L
Digoxin	≥ 3.0	nmol/L
Ethanol	≥ 30	mmol/L
Gentamicin	Peak ≥ 10.00; Trough ≥ 2.00	mg/L
Glucose	≤ 2.5 or ≥ 25.0	mmol/L
Ionized Calcium	≤ 0.85 or ≥ 1.55	mmol/L
Lactate Venous - Grey top Arterial - Syringe	≥ 4.0 ≥ 3.4	mmol/L
Lithium	≥1.4 (≥60 years of age) ≥1.5 (<60 years of age)	mmol/L
Magnesium	≤ 0.40 or ≥ 2.00	mmol/L
MetHb	≥ 0.100	F. T. Hb
Osmolality	≤ 250 or ≥ 350	mmol/Kg
Phenytoin	≥ 100	µmol/L
Phosphate	< 0.40 or ≥ 3.00	mmol/L
Potassium	≤ 2.7 or ≥ 6.0 (≤ 2.5 for Dialysis patients only)	mmol/L
Salicylate	≥ 2.2	mmol/L
Sodium	≤ 120 or ≥ 160	mmol/L
Thiocyanate	> 2.0	mmol/L
Tobramycin	Peak ≥ 10.00; Trough ≥ 2.00	mg/L
Total Calcium /Systemic Ionized Calcium ratio	≥ 2.5
Troponin T High Sensitivity	Dependent on location: call the first critical result ≥ 100 (at each location) call the second critical result if it doubles the first call anytime the result returns to below 100ng/L and then goes above > 100ng/L is to be treated as a first time critical call on 30th day if above 100, treat as day 1 (call) independent of location	ng/L
Urea	≥40.0 call the first critical result ≥40.0 call on 60^th day if above 40, treat as day 1 (call) do not call Dialysis patients	mmol/L
Urate	≥ 1000 (Dialysis or Nephrology patients: need NOT call)	µmol/L
Valproic Acid	≥ 1000	µmol/L
Vancomycin	Trough ≥30.01; Random ≥30.01	mg/L

Appendix 2: Table of Paediatric (< 1 yr.) Critical Limits

Tests	Critical limits	Units
Blood Gases pH pCO2 pO2 Bicarbonate	< 7.23 or > 7.45 < 30 or > 70 Call whenever pCO2 ≤ 35 Do not call any pO2 results ≤ 10 or ≥ 40	mm Hg mm Hg mmol/L
Cord Blood Gases pH	≤ 7.00 phone critical result to NICU Fellow on-call through locating
Ammonia	≥ 99	µmol/L
Bilirubin, total	> 300	µmol/L
Glucose	< 2.6 or > 10.0 Provide a preliminary report if the glucose is < 2.0 or > 25.0 prior to repeating test result.	mmol/L
Ionized Calcium	≤ 0.85 or ≥ 1.55	mmol/L
Lactate	≥ 4.0	mmol/L
Na	< 120 or > 155	mmol/L
Triglyceride	> 3.0	mmol/L
Vancomycin	Peak > 40; Trough < 5	mg/L
Note: Critical Limits for the Neonatal Intensive Care Unit (NICU) may differ on the basis of the gestational age of the infant. There may be NICU-specific action protocols for these and other analytes, and such SOPs take precedence over the general action protocols listed in the main body of this SOP.