1. Postanalytical Phase of Laboratory Testing
Module 4
Postanalytical Phase of Laboratory Testing

2. Once an accurate test result is obtained the lab must
Report the result in a timely manner by:
Using an electronic process allowing for acceptable results to be transmitted electronically via an ‘interface’ between the analyzer and lab information system(LIS) and then via another ‘interface’ between the LIS and the electronic medical record (EMR) or….
Transcribing accurately the results to a paper or written medical record
The vast majority of results are transmitted by the first mechanism

3. “Critical Results”
“Critical results” of tests fall significantly outside the normal range, may indicate a life threatening situation, and may require immediate clinical action
Values are decided upon in collaboration with insititution laboratory directors and physician leadership
The objective is to provide the responsible licensed caregiver with these results within an established time frame so that the patient can be promptly treated
The reporting of critical results in a timely basis is a National Hospital Patient Safety Goal

4. “Critical Results”
Current regulations require that the person receiving the report of the critical result be asked to read back the results to the lab staff member to ensure correct information was communicated
This must be documented in the medical record

5. Examples of Clinical Laboratory Critical Results
Less than Greater than
Hemoglobin
Ages 1 mo-adult g/dL g/dL
Ages 1 day – 1 mo g/dL g/dL
Ages 0 -1 day g/dL g/dL
Ionized Calcium (ICAL) mmol/L mmol/L
(Ages months) mmol/L mmol/L
Lithium (LI) mmol/L (Toxic Range)
Partial Thromboplastin Time (PTT) seconds
Potassium (K) (serum or plasma) 2.8 mmol/L 6.1 mmol/L
Potassium (K) (whole blood) mmol/L 6.5 mmol/L
Critical Results in Microbiology
The physician or designate is notified for:
Positive CSF smears

6. It Starts and Ends with the Patient
Remember that the laboratory testing process begins and ends with patient care
All laboratory tests MUST be interpreted in light of the clinical situation
Although lab testing may yield unexpected results that are critical in guiding further patient evaluation and management, clinicians must be vigilant for the possibility of spurious results from improper specimen collection, mislabeled specimens, clerical errors and other preanalytic, analytic and postanalytic ‘misadventures.’

7. Clinicians should ALWAYS feel free to contact the clinical laboratory staff and/or lab directors about any test result - they are members of your healthcare team.

8. Proceed to Module 5 “Normal Values”: How are Normal Reference Ranges Established?