Critical Laboratory Tests and Values

All phone calls made to report critical values are documented in the Laboratory Information System. To comply with patient safety goals, the person taking the call must read back the patient’s name, the hospital number and all laboratory results.

Critical test results will be telephoned to the referring facility as soon as possible. If in the event, contact cannot be made at that time, the result will be forwarded to UI Diagnostic Laboratories Client Services for call back during business hours.

Chemistry and Toxicology
Less Than
Greater Than
Ammonia (*see below)   150 (<18 years old)
Bilirubin, Total  
10.0 mg/dL for first 24 hrs
13.0 mg/dL for 1-30 days
6.0 mg/dL
13.0 mg/dL
Carbon Dioxide
10 mEq/L
50 mEq/L
Cortisol (*see below)
2.0 mcg/dL
300 mg/dL
Ethylene Glycol   20 mg/dL
Glucose      **Adults
50 mg/dL
40 mg/dL
450 mg/dL
300 mg/dL
Isopropanol   10 mg/dL
1.0 mg/dL
4.7 mg/dL
Methanol   10 mg/dL
Phosphorus, Inorganic (*see below) 1.0 mg/dL  
Potassium    Adults > 16 years
                   Peds (0-15 years)
2.8 mEq/L
3.0 mEq/L
6.2 mEq/L
6.5 mEq/L
Propylene Glycol   100 mg/dL
Salicylate   50 mg/dL
120 mEq/L
160 mEq/L
Troponin T
>100 ng/L (outpatient only, excluding Emergency Department)

 *Ammonia, Cortisol serum/plasma concentrations less than 2.0 mcg/dL and phosphorus (inorganic) less than 1.0 mg/dL are
   treated as significant (not critical) values.

**Also applies to glucose levels determined during glucose tolerance tests.

Results Called on these Critical Therapeutic Drug Levels:
Test Name Greater Than
Acetaminophen 40 μg/mL
Amikacin 35 μg/mL
Carbamazepine 12 μg/mL
Digoxin 2.0 ng/mL for adults
Gentamicin 15 μg/mL
Lidocaine 5 μg/mL
Lithium 1.4 mEq/L
Phenobarbital 60 μg/mL
Phenytoin 40 μg/mL
Procainamide 16 μg/mL
Salicylate 40 mg/dL
Theophylline 20.0 μg/mL
Tobramycin 10 μg/mL
Valproic Acid 150 μg/mL
Vancomycin 30 μg/mL

Requests for assistance with interpretation should be directed to UIDL Client Services at 319-356-8588 (toll-free at 1-866-844-2522).

Less Than or Equal to
Greater Than or Equal to
 80 mg/dL
55% (adult)
6 gm/dL (<7 outpatients)
22 gm/dL (adult)
HIT (Heparin dependent antibody)
Results: Positive
INR (venous)  
Platelet Count
10 k/mm3
1,000 k/mm3
PTT (Outpatient only)  
 50 seconds
White Blood Count (WBCT)
1.0 k/mm3
50.0 k/mm3

Critical or Significant values: patient results are called to the physician or service area as soon as results are available.

1. Critical value patient results include:
    a. Positive direct examination from sterile body fluid/site
        1) Cerebrospinal fluid
        2) Joint fluid
        3) Pericardial fluid
        4) Pleural fluid
        5) Peritoneal fluid
    b. Positive blood culture (initial gram stain report)
    c. Positive Legionella pneumophila antigen (also page on-call epidemiologist)
    d. Positive Cryptococcus neoformans antigen
    e. Positive malaria smears

2. Significant patient results include:
    a. Positive STAT gram stain results
    b. Negative STAT gram stain results from the Operating Room. If patient is out of the Operating Room when
        results become available, results will not be called.
    c. Positive direct examination from intraoperative specimens
    d. Positive direct gram stain with hyphal forms seen, both sterile and non-sterile sites.
    e. Positive culture of sterile body fluid (Do not call identical result within 5 days)
        1) Cerebrospinal fluid
        2) Joint fluid
        3) Pleural fluid
        4) Pericardial fluid
        5) Peritoneal fluid
        6) Intraoperative body fluids
    f. Positive direct antigen tests
        1) Pneumocystis carinii
        2) Malaria
    g. Epidemiology considerations (call to floor)
        1) Methicillin-resistant Staphylococcus aureus (8JC; NICU; 4JPE; 7RC only)
        2) Vancomycin-resistant enterococci (8JC; NICU; 4JPE; 7RC only)
        3) ESBL (inpatient's)
    h. Epidemiology considerations (call floor and on-call epidemiologist pager)
        1) Acid-fast bacilli smear
        2) M. tuberculosis (culture or PCR)
        3) Legionella pneumophila (urine antigen or growth from environmental culture)
        4) Neisseria meningitidis (CSF gram stains with gram negative diplococci or growth from normally sterile site)
        5) Category A bioterrorism agents (Bacillus anthracis, Yersinia pestis, Francisella tularensis,
            Clostridium botulinum toxin, Smallpox, Viral hemorrhagic fever)
        6) Extended spectrum B-lactamases - call floor inpatient's only
        7) Multi-drug resistant gram negative rods - inpatient's only
    i. Culture or molecular detection of following organisms from any source:
       (If patient is from OB/GYN do not call results unless the organism is isolated from blood or normally sterile body fluids.)
        1) Streptococcus pyogenes
        2) Virus Detection
        3) Herpes Simplex (HSV), or Enterovirus PCR
        4) Dimorphic fungi
        5) Clostridium difficle - Inpatient's only
        6) Cryptococcus neoformans
    j. Positive ocular cultures (other than conjunctiva)
    k. Molecular detection or culture of stool pathogens
        1) Salmonella spp.
        2) Shigella spp.
        3) Campylobacter spp.
        4) Yersinia spp.
        5) Escherichia coli H7;O157
    l. Culture of potential bioterrorism agents
        1) Francisella tularensis
        2) Bacillus anthracis
        3) Brucella spp.
        4) Yersinia pestis
        5) Coccidiodes immitis
        6) Burkholderia mallei or pseudomallei

3. Calling Algorithm:
Follow Department of Pathology guidelines (500.020) entitled "Reporting Critical Tests and Critical Values." This policy defines authorized staff that may accept critical values and provides a detailed calling algorithm. The results must be "read back" by the authorized staff and the call documented in Comm log.

For OB/GYN patients only smear or culture results from blood cultures and normally sterile body fluid specimens are phoned on a STAT basis.