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Alberta Precision Laboratories (APL) Test Directory

Critical Values

Clinical Biochemistry: CLS and CRL



CLS and
Calgary Rural Labs (CRL)

Critical Values

To be called as soon as the result is available
24 hours per day.
All Patients,
Unless Otherwise Noted

Acetaminophen  Greater than 250 umol/L
Acetone  Greater than 6 mmol/L
Amikacin  Pre: greater than 10.0 mg/L
 Post: greater than 40.0 mg/L
 Random: greater than 40.0 mg/L
Amiodarone  Greater than 5.4 umol/L
Ammonia  Less than 17 years: greater than 110 umol/L
 17-150 years: greater than 200 umol/L
Bilirubin, Total

 Less than 31 days: greater than 300 umol/L
 Piccolo (for VHF testing) only - Less than 31 days: greater than 313 umol/L

 Blood Gases


 pH  Less than 7.30 Greater than 7.51 
 pCO2  Less than 20 mmHg Greater than 70 mmHg 


 Less than 60 mmHg  


 pH  Less than 7.15 Greater than 7.55 
 pCO2  Less than 15 mmHg Greater than 55 mmHg if pH is less than 7.2 
 Bicarbonate (HCO3)  Less than 10 mmol/L  Greater than 40 mmol/L
 Hemoglobin   Less than or equal to 7 days  Less than 100 g/L  
 Hemoglobin  Greater than 7 days  Less than 70 g/L  

ACH, FMC, PLC, RGH and SHC: ONLY Emergency Department Venous Blood Gas critical values performed by Chemistry at these sites are communicated by CLS.               

Calcium, Total  Less than 1.65 mmol/L
 Greater than 3.25 mmol/L
Calcium, Free or Ionized  Less than 0.85 mmol/L
 Greater than 1.50 mmol/L

 Greater than 65 umol/L

Carboxyhemoglobin  Greater than 15%
Clozapine  Greater than 3500 nmol/L
 When result is reported greater than 7 days post collection, result will be faxed.
Desmethylclozapine  Greater than 2000 nmol/L
 When result is reported greater than 7 days post collection, result will be faxed.
Digoxin  Greater than 2.6 nmol/L
Ethanol  Greater than 65.0 mmol/L
 Not communicated to Emergency Departments at FMC, PLC, RGH and SHC.
Ethylene Glycol  Greater than 2 mmol/L
Gentamicin  Pre: greater than 1.9 mg/L
 Post: greater than 14.9 mg/L
 Random: greater than 14.9 mg/L
Glucose  Less than 30 days: 
        Less than 2.0 mmol/L
        Greater than 24.9 mmol/L
 30 days - 150 years:
        Less than 2.6 mmol/L
        Greater than 24.9 mmol/L 
Iron  Less than 12 years: greater than 54 umol/L
Isopropanol  Greater than 8 mmol/L
Lactate  Greater than 4.0 mmol/L
Lithium  Greater than 2.00 mmol/L
Magnesium  Less than 0.40 mmol/L
 Greater than 1.90 mmol/L
Methanol  Greater than 2 mmol/L
Methemoglobin  Greater than 10 %
Oncology Cortisol  Oncology patients only: 
        Less than 50 nmol/L
Osmolality - Serum

 Acute care patients only:
        Less than 250 mmol/kg
        Greater than 320 mmol/kg
 Not communicated to Emergency Departments at FMC, PLC, RGH and SHC.

Overdose Iron  Less than 12 years: greater than 54 umol/L
Phenobarbital  Greater than 190 umol/L
Phenytoin (Dilantin)   Less than 4 months: greater than 80 umol/L
 4 months - 150 years: greater than 120 umol/L
Phenytoin, Free (Dilantin, Free)  Greater than 12.0 umol/L
Phosphate  Less than 0.40 mmol/L

 Less than 29 days:
       Less than 3.0 mmol/L
       Greater than 6.4 mmol/L
 29 days - 364 days:
       Less than 3.0 mmol/L
       Greater than 6.0 mmol/L
 1 year - 17 years:
       Less than 3.0 mmol/L
       Greater than 6.0 mmol/L
 18 years - 150 years:
       Less than 2.6 mmol/L
       Greater than 6.2 mmol/L

Primidone (Mysoline)  Greater than 70.0 umol/L
Salicylate  Greater than 2.20 mmol/L
Sirolimus  Greater than 30 ug/L
Sodium  Less than 120 mmol/L
 Greater than 155 mmol/L
Tacrolimus  Greater than 30 ug/L
Theophylline  Greater than 110.0 umol/L
Tobramycin  Pre: greater than 1.9 mg/L
 Post: greater than 14.9 mg/L
 Random: greater than 14.9 mg/L
 ACH CF patients: greater than 25.0 mg/L
Troponin I Access 
 Greater than 0.50 ug/L
Troponin I Stratus 
 Greater than 0.50 ug/L
Troponin I Triage Meter
 VHF patients only: greater than 0.50 ug/L
Troponin I Vidas High Sensitivity
 Greater than 99 ng/L
Troponin T High Sensitivity

 Greater than 52 ng/L
 Emergency and inpatient critical TNT will not be communicated by telephone; only physicians of community patients with a critical value will be contacted.

Valproic Acid  Greater than 1150 umol/L
Vancomycin  Pre: greater than 25.0 mg/L
 Random: greater than 60.0 mg/L


Hematology: CLS and CRL

For Hematology critical values, see Laboratory Report.


Appropriate medical staff will be notified by fax or phone of the following results:

1. All sterile site specimens, positive by Gram stain and/or culture, including:
•blood cultures
•central nervous system specimens (e.g. CSF)
•sterile fluids
•vitreous fluid/corneal scrapings

2. Eye cultures: all positive for Neisseria gonorrhoeae or Pseudomonas aeruginosa

3. Sinus cultures: all positive for agents of mucormycosis (e.g. Zygomycetes)

4. Any other specimen positive for the following bacteria:
Clostridium perfringens, C. botulinum, C. tetani
•Corynebacterium diphtheriae
•Listeria spp.
•Cryptococcus neoformans, C. gattii

5. Any specimen positive for extremely resistant organisms, including:
•carbapenemase producing organisms (CPO)
•glycopeptide/vancomycin intermediate or resistant Staphylococcus aureus (GISA/VISA/VRSA)

6. Any specimen positive for risk group 3 (RG3) bacteria, including:
Bacillus anthracis
•Yersinia pestis
•Burkholderia pseudomallei, B. mallei

7. Any specimen positive for risk group 3 (RG3) fungi, including:
•Coccidioides immitis/ posadasii
•Histoplasma capsulatum
•Blastomyces dermatitidis
•Talaromyces (Penicillium) marneffei
•Paracoccidioides brasiliensis
Cladophialophora bantiana

8. Any specimen positive for the following parasites:
•Malaria (Plasmodium spp.)
Any other blood parasite (e.g. microfilariae)
•Entamoeba histolytica
•Pneumocystis jirovecii
9. Acid-fast bacilli (AFB): positive acid-fast stain or culture
10. Influenza/RSV: positive in inpatient or transplant recipient

11.All notifiable disease isolates, notifiable by fastest means possible: http://www.health.alberta.ca/professionals/notifiable-diseases-guide.html



  • Critical values are test results that are so abnormal that they generally indicate severe illness and require immediate medical intervention. For this reason, these values must be communicated to the attending physician immediately.
  • While critical values are generally indicative of acute disease requiring intervention, there are some patients with marked metabolic derangements that are physiologically fairly well compensated. For example, renal patients can have chronically elevated potassium levels that are surprisingly well tolerated. A general rule of thumb is that chronic changes in physiological status are much better tolerated than rapid alterations.
  • Some physicians or units may decline communication of critical values. In these cases, written documentation must be produced for the laboratory to comply with this request.

Some testing areas may wish to phone some abnormal results, and these discretionary decisions have not been built into the critical value list.