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Critical Values

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Critical values are potentially life threatening laboratory results that must be conveyed immediately to the physician or other health care professional so that therapeutic measures can be instituted rapidly. Main Line Health Laboratories maintains critical values for routine laboratory studies, therapeutic drug monitoring, microbiology testing, and blood bank results.

When a critical value is encountered Main Line Health Laboratories automatically repeats the test in question. Once the critical value is verified, Main Line Health Laboratories will report the value to your office, usually by telephone. If an answering service is reached we will inform them that you have a critical laboratory result, provide the patient name and request that you contact our testing facility. If your answering service is authorized to accept critical values the result will be left with the service. Communication of critical values is documented on the patient's laboratory report. If your office uses an answering machine after the close of business and no physician can be reached, Main Line Health Laboratories will leave critical results on the answering machine and follow up the next working day.

Click the links below to view the list of test results considered critical values by MLHL.

General Laboratory Tests
Therapeutic Drug Monitoring
Microbiology Critical Values
Other Called Microbiology Reports
Blood Bank Critical Values

Critical Values For General Laboratory Tests

TEST	LOW( < OR = )	HIGH( > OR = )
Hemoglobin	7 g/dl	20 g/dl
White cell count	2500/ mm³	30,000/mm³ *
Platelet count	50,000/mm³ 100,000/mm³ (NICU)	1,000,000/mm³
Fibrinogen	100 mg/dl	None
Prothrombin Time	None	INR 6.0
PTT, Activated	None	143 sec.
Alcohol	None	350 mg/dl
Bilirubin(newborn)	None	15 mg/dl
Calcium,ionized	0.77 mmol/L	1.59 mmol/L
Calcium, serum	6 mg/dl	13 mg/dl
BUN, serum	None	80 mg/dl**
Creatinine, serum	None	5.0 mg/dl**
Glucose, serum	50 mg/dl	450 mg/dl
Magnesium, serum	1.0 mg/dl	4.0 mg/dl
Potassium, serum	2.8 mEq/L	6.0 mEq/L 7.0 mEq/L (NICU)
Sodium, serum	125 mEq/L	160 mEq/L
Troponin I	None	0.4*** ng/mL
Total C02, serum	10 mEq/L	40 mEq/L
pCO2, arterial or capillary	20 mmHg	70mmHg
PH, arterial or capillary	7.25	7.60
p02, arterial or capillary	40 mmHg	None
Positive Initial Malaria Identification
Positive Culture: Blood, CSF, Body Fluid, Tissue
Positive Gram Stain: CSF, Body Fluid, Tissue
Positive CSF Finding (other): Cryptococcal Antigen

*Unless a known chronic leukemia patient
**Unless known patient with renal failure.
***Unless known patient with high troponin.

Critical Values For Theraputic Drug Levels

DRUG	THERAPEUTIC LEVEL	TOXIC LEVELS (Call Results)
Antibiotics
Gentamicin	Peak: 4.0-10.0 mcg/mL Trough: 0.0-2.0 mcg/mL Single day dosing: 0.0-1.0 mcg/mL	Peak:>10.0 mcg/mL Trough: >2.0 mcg/mL Single day dosing: >1.0 mcg/mL
Tobramycin	Same as above	Same as above
Vancomycin	Peak: 30.0-40.0 mcg/mL Trough: 5.0-10.0 mcg/mL	Peak: >40.0 mcg/mL Trough:>12.0 mcg/mL
Anticonvulsants
Carbamazepine (Tegretol)	8.0-12.0 mcg/mL (single agent) 6.0-10.0 mcg/mL(multiple drugs)	>15.0 mcg/mL >12.0 mcg/mL
Phenobarbital	15.0-40.0 mcg/mL	>50.0 mcg/mL
Phenytoin (Dilantin)	10.0-20.0 mcg/mL	>25.0 mcg/mL
Valproic Acid	50.0-100.0 mcg/mL	>125.0 mcg/mL
Bronchodilators
Caffeine	10.0-20.0 mcg/mL	>20.0 mcg/mL
Theophylline	5.0-15.0 mcg/mL (adult) 10.0-20.0 mcg/mL (0-19 years)	>20.0 mcg/mL >20.0 mcg/mL
Cardiovascular
Digoxin	0.5-2.0 ng/mL	>2.4 ng/mL
Procainamide	4.0-10.0 mcg/mL	>10.0 mcg/mL
PA + NAPA levels in renal insuffuciency	PA + NAPA: 5.0-30.0 mcg/mL	>30.0 mcg/mL
Quinidine	1.5-5.0 mcg/mL	>5.0 mcg/mL
Other Agents
Acetaminophen	10-30 mcg/ml	>120 mcg/ml
Cyclosporin	100-300 ng/ml	>300 ng/ml
Lithium	0.5-1.0 mEq/L	>1.1 mEq/L
Salicylate	<20 mg/dl	>30 mg/dl

Critical Values for Microbiology Testing

FINDING	CALL TO PHYSICIAN OR DESIGNEE	CALL TO NURSING UNIT OR PHYSICIAN OFFICE	CALL TO INFECTION CONTROL PRACTITIONER
Positive blood culture	X^a	X^b
Significant CSF findings Positive direct exam. Positive culture Positive Cryptococcal antigen	X		If Gram (-) diplococci are observed on Gram stain or if N. meningitidis is recovered by culture.
Positive Gram stain or culture of:: Internal organ tissue Sterile Body fluids	X
AFB Findings: Positive smear. Positive AFB Culture (if original smear is negative). Identification of Mycobacterium tuberculosis.	X	X^c	X
Positive malaria smear	X
^a Results are Called to physician 0700 - 2200. After 2200, nursing unit is called and the physician is notified the following morning. ^b BMH and PMH only. ^c Only if patient is still an Inpatient.

Other Non-Critical Microbiology Reports Called

FINDING	CALL TO PHYSICIAN OR DESIGNEE	CALL TO NURSING UNIT OR PHYSICIAN OFFICE	CALL TO INFECTION CONTROL PRACTITIONER
Positive catheter tip (>15 CFU)		X
Respiratory tract specimen positive for N. meningitidis		X	X
Identification of vancomycin resistant Enterococci			X^a
Genital specimens – positive for group B Strep	X
Throat specimen - Positive Culture or Antigen test for group A Strep	X
Positive culture for N. gonorrhoeae	X
Positive Amplified test for N. gonorrhoeae DNA	X
Positive Amplified test for Chlamydia trachomatis DNA	X
Positive culture for enteric pathogen	X
Positive O+P exam	X
Positive Test for Clostridium difficile toxins A/B		X^b
^{^a Inpatient Only ^b PMH and BMH Only}

Critical Values for Blood Banking

CRITICAL RESULT	PATIENT'S PHYSICIAN NOTIFIED BY MEDICAL DIRECTOR	PATIENT CARE UNIT NOTIFIED BY BLOOD BANK TECHNOLOGIST	BLOOD BANK MEDICAL DIRECTOR OR PATHOLOGIST ON CALL	RISK MANAGEMENT	BLOOD SUPPLIER	VERIFICATION AND READ BACK
Acute Hemolytic Transfusion Reaction	X	X	X	X	X If due to ARC Product Mislabeling	X
Detection of Bacterial Contamination of Blood Product	X	X	X	X	X	X
Positive DAT - Specific Antibody Identified in Eluate		X	X			X
Antigen Negative red cells not available on site for inpatient transfusion		X				X

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