Module 5
Postanalytical Phase of
Laboratory Testing
Once an accurate test result is
obtained the lab must
O Report the result in a timely manner by:
O 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….
O Transcribing accurately the results to a paper or
written medical record
O The vast majority of results are transmitted by
the first mechanism
Photo by Theresa Kristopaitis, MD
Case Scenario 1
O A 68-year old woman with atrial fibrillation
chronically anticoagulated with warfarin
presents for her monthly INR blood draw.
She relates to the nurses that her husband
died unexpectedly 3 weeks ago and she has
had a very poor appetite since.
Photo by Theresa Kristopaitis, MD
Case Scenario 1
Result
Component
Value Flag
PROTHROMBIN TIME 68.6 H
INR RATIO
5.3
H
Reference Range
9.2 - 11.8 SEC
Comment:
SUGGESTED THERAPEUTIC RANGE FOR CONTROL OF ORAL ANTICOAGULANT THERAPY
INR 2.0-3.0 FOR DVT/PE, TISSUE VALVE, ATRIAL FIB, MI-STROKE PREVENT
INR 2.5-3.5 FOR MECHANICAL VALVE
Case Scenario 1
Per the laboratory guidelines, the INR result is considered
a “critical result”. What is the next appropriate step taken
by the laboratory technologist?
A. Call the patient with the abnormal test result
B. Communicate the INR result directly to the ordering
physician or their designate
C. Notify the coagulation laboratory director of the test
result
D. Order a STAT re-draw of the patient sample and notify
the patient
E. Rush the written result report into the medical record
“Critical Results”
O “Critical results” of tests fall significantly outside
the normal range, may indicate a life threatening
situation, and may require immediate clinical
action
O Values are decided upon in collaboration with
institution laboratory directors and physician
leadership
O 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
O The reporting of critical results in a timely basis is
a 2013 JCAHO National Hospital Patient Safety
Goal
“Critical Results”
O 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
O This must be documented in the medical
record
Photo Theresa Kristopaitis, MD
Other Examples of Clinical Laboratory Critical Results
Less than Greater than
Hemoglobin
O Ages 1 mo-adult
O Ages 1 day – 1 mo
O Ages 0 -1 day
7.0 g/dL
Ionized Calcium (ICAL)
(Ages 0 - 6 months)
0.85 mmol/L
1.50 mmol/L
0.95 mmol/L
1.65 mmol/L
7.0 g/dL
7.0 g/dL
19.0 g/dL
20.5 g/dL
24.0 g/dL
Lithium (LI)
2.0 mmol/L
(Toxic Range)
Partial Thromboplastin Time (PTT)
100 seconds
Potassium (K) (serum or plasma)
Potassium (K) (whole blood)
Critical Results in Microbiology
The physician or designate is notified for:
Positive CSF smears
2.8 mmol/L
2.5 mmol/L
6.1 mmol/L
6.5 mmol/L
It Starts and Ends with the Patient
O Remember that the laboratory testing
process begins and ends with patient care
O All laboratory tests MUST be interpreted in
light of the clinical situation
O 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.’
Laboratory Staff are Members of
the Healthcare Team!
O Clinicians should ALWAYS feel free to contact lab
directors and/or clinical laboratory staff with
questions about any lab test:
O Interpretation of results
O Assurance of quality of a test
O Discussion of potential sources of error or
variables to be considered in test interpretation
O Determination of need for a specialized test
O Proceed to Module 6 “Normal Values”:
How are Normal Reference Ranges
Established?