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Automated analyzers and documented competency

15 min

  • Choose the next CBC check from flags, red cell indices, lipemia, or cold agglutination
  • Match a coagulation measurement principle to its likely interference
  • Recognize when an automated identification or susceptibility result needs confirmation
  • Tell course attendance from documented competency assessment

Read the full reference

Try first

Try first

A complete blood count (CBC) shows a mean cell hemoglobin concentration (MCHC) of 41.5 g/dL. The analyzer raised no flag, and the patient's MCHC last week was 33.4 g/dL. What do you do?

The next section explains it.

Right. The next section explains why.

The next section explains it.

The next section explains it.

Get the idea

A flag is a question

A hematology analyzer combines impedance, light scatter, fluorescence and absorbance, and its flag rules detect selected patterns only. Some artifacts pass without a flag and show up as indices that break their usual relationships.1

  • Cold agglutination: clumped red cells pass the aperture together and count as one large event. The RBC count falls, and the MCV and the calculated MCHC rise.
  • Lipemia or a very high white cell count: turbidity adds to the photometric hemoglobin, raising the hemoglobin, MCH and MCHC.1

The laboratory's procedure maps each pattern to its fix, such as warming the specimen, dilution, an alternate method, a manual count or a film review. A rerun without that fix repeats the artifact.1

Each coagulation principle has its own interference

Each detection principle reads its own signal, so each has its own interferences.2

Detection principleSignalMain interference
Photo-optical clot detectionLight change as fibrin formsHemolysis, icterus, lipemia, turbidity
Mechanical clot detectionMovement of a ball or probe as the clot formsVery weak clots, vibration
ChromogenicColor released from a cleaved substrateEndogenous color, other enzyme inhibitors

A heparin-calibrated chromogenic anti-Xa assay reads all factor Xa inhibition. Residual apixaban or rivaroxaban during a switch to heparin makes the heparin result read falsely high.3

Automated identification needs a pure isolate

MALDI-TOF mass spectrometry matches the spectrum of the colony it receives against its reference library. A mixed colony, a poor preparation or an organism missing from the library can return a wrong identification with a high score. A Gram stain or susceptibility pattern that does not fit the named organism is a reason to purify and identify again.4

Competency is shown by performance

Training teaches the procedure. Competency assessment shows the person performs it correctly. For moderate- and high-complexity testing, each test's assessment covers six procedures:5

  1. Direct observation of routine testing.
  2. Monitoring of result recording and reporting.
  3. Review of worksheets, QC, proficiency testing and maintenance records.
  4. Direct observation of instrument maintenance and function checks.
  5. Testing of previously analyzed, blind or proficiency testing samples.
  6. Assessment of problem solving.

All six are documented every 6 months in the first year of testing and yearly after that. A new analyzer needs training and documented competency before the person reports patient results.5

References
  1. Gulati G, Uppal G, Gong J. Unreliable automated complete blood count results: causes, recognition, and resolution. Ann Lab Med. 2022;42(5):515-530. doi:10.3343/alm.2022.42.5.515
  2. Clinical and Laboratory Standards Institute. One-Stage Prothrombin Time (PT) Test and Activated Partial Thromboplastin Time (APTT) Test. 3rd ed. CLSI standard H47. Clinical and Laboratory Standards Institute; 2023. Accessed September 26, 2026.
  3. Bazydlo LAL, Marin MJ, Merrill AE, Man LM, Oladipo OO, Harris NS. ADLM guidance document on coagulation testing in patients using direct oral anticoagulants. J Appl Lab Med. 2025;10(6):1675-1690. doi:10.1093/jalm/jfaf155
  4. Patel R. MALDI-TOF MS for the diagnosis of infectious diseases. Clin Chem. 2015;61(1):100-111. doi:10.1373/clinchem.2014.221770
  5. Centers for Medicare & Medicaid Services. Assessing Personnel Competency. Revised May 2025. Accessed September 26, 2026.

Watch one

A CBC from an outpatient clinic arrived after a cold morning in transit. The analyzer reports:

  • RBC count 2.00 × 10⁶/µL, hemoglobin 11.6 g/dL, hematocrit 23.4%
  • MCV 117 fL, MCH 58.0 pg, MCHC 49.6 g/dL
  • No flag. Her CBC last month showed hemoglobin 11.9 g/dL, MCV 92 fL and MCHC 33.6 g/dL.

What do you do before release?

  1. Read the MCHC first: 49.6 g/dL is far above the hemoglobin concentration a red cell can hold.

    MCHC has a physiologic ceiling, and a value far above it is an artifact until shown otherwise.

  2. Read the pattern: the RBC count is low and the MCV high, with a hemoglobin close to her usual. Clumped red cells counted as single large events give this pattern.

    The pattern of which values moved points to the cause.

  3. Inspect the tube for visible agglutination and look at a blood film for red cell clumps.

    Agglutinates in the tube or on the film confirm the cause.

  4. Warm the specimen at 37 °C under the laboratory's validated procedure, then rerun it warm.

    Warming disperses cold agglutinates so the cells pass the aperture one at a time.

  5. Check the warm rerun: RBC count 3.78 × 10⁶/µL, MCV 93 fL, hematocrit 35.2%, MCH 30.7 pg, MCHC 33.0 g/dL.

    Indices that fit together again show the artifact has been removed.

Warm the specimen to 37 °C and rerun it. Release the warm results, with MCHC 33.0 g/dL, as the procedure directs.

Your turn

Problem 1 of 3

A coagulation analyzer uses photo-optical clot detection. Which pairing names its signal and an interference that affects it?

Correct. A photo-optical endpoint follows the change in transmitted or scattered light as fibrin forms. Hemolysis, icterus, lipemia, and other turbidity add their own optical signal and can distort the reaction curve.

Incorrect. Sensor movement is the mechanical or electromechanical principle, where clot geometry, vibration, and very weak clots limit the endpoint. A photo-optical system reads light.

Incorrect. Color released from a laboratory-made substrate is chromogenic detection, used for enzyme and anti-Xa assays. A photo-optical clot endpoint reads the light change as fibrin forms.

Hint
  1. Photo-optical means the analyzer watches light.
  2. Ask which specimen problems change how light passes through plasma.
  3. Each option names a different detection principle. Match the signal first.

Review Hemostasis instrumentation

Problem 2 of 3

MALDI-TOF identifies a urine isolate as Escherichia coli with a high score. A Gram stain of the same colony shows gram-positive cocci, and the plate holds two colony types. What do you do?

A high score cannot rescue a mixed colony. The Gram stain conflicts with the name, so the identification cannot be released.

Accepted an automated ID that conflicts with the culture

A mixed culture, poor preparation, a low-confidence score, or an organism missing from the database can produce a wrong identification that looks confident. A susceptibility pattern that does not fit the organism signals the same problem. Releasing it reports the wrong organism and can apply the wrong susceptibility breakpoints.

Neither organism has been identified from a pure isolate yet. Reporting both names adds a second unconfirmed result.

The Gram stain and the two colony types point to a mixed pick. Each organism is identified from its own pure colony before anything is reported.

Hint
  1. The score describes how well the spectrum matched the library.
  2. Escherichia coli is a gram-negative rod.

Review Automated microbiology systems

Problem 3 of 3

A technologist in her third year runs glucose on a moderate-complexity analyzer. Her annual competency file for glucose holds only her passing results on this year's proficiency testing samples. Is her glucose competency documented?

Proficiency testing samples count toward testing of previously analyzed or blind samples. Direct observation, record review, instrument checks and problem solving still need their own documentation.

Proficiency testing contributes to one of the six procedures. It leaves specimen handling, recording, maintenance and problem solving unassessed.

After the first year, all six procedures are documented at least once a year.

Review Training, competency, and continuing education

Use it

  • A man (MRN 0194306) is switching from apixaban to an unfractionated heparin infusion.
  • His last apixaban dose was 8 hours before collection. The heparin infusion started 4 hours before collection.
  • A heparin anti-Xa is ordered, and the laboratory's assay is chromogenic and heparin-calibrated.
  • The new coagulation analyzer went live this week.
  • Sam, the technologist on the bench, transferred last week. His file holds the vendor's course certificate for the new analyzer and no competency assessment.
TestResultPreviousReference intervalFlag
Heparin anti-Xa1.38 IU/mL0.30–0.70 IU/mLHigh
PT14.9 s14.6 sYesterday 07:1011.5–14.5 sHigh
APTT52 s33 sYesterday 07:1025–35 sHigh
Platelet count214 × 10³/µL226 × 10³/µLYesterday 07:10135–317 × 10³/µL

Specimen: H 6, L 12, I 2. Citrate plasma, correctly filled; drawn from the arm without the infusion.

Decision 1 of 3

What best explains the anti-Xa of 1.38 IU/mL?

The assay reads all factor Xa inhibition. Apixaban taken 8 hours ago still inhibits factor Xa, so the result includes apixaban activity.

Read anti-Xa as heparin during an apixaban transition

A chromogenic anti-Xa method avoids clot-detection problems and still reads any factor Xa inhibition, so residual apixaban or rivaroxaban makes a heparin anti-Xa result appear falsely high. Each principle has its own interferences: turbidity for optical clot detection, weak clots for mechanical detection, and drugs or endogenous color for chromogenic assays.

The lipemia index is 12, and the assay is chromogenic. It reads color from a cleaved substrate and detects no clot.

A heparin-calibrated chromogenic anti-Xa counts every factor Xa inhibitor present. With apixaban taken 8 hours ago, the result reads falsely high as a heparin level.

Review Hemostasis instrumentation

Decision 2 of 3

What does the laboratory do with the result?

The protocol accounts for the drug, the dose timing and the assay. Its comment tells the team that the anti-Xa includes apixaban activity.

Clot-based tests carry their own sensitivity to apixaban and to reagents. Switching to the APTT leaves the same problem in another form.

Reported without comment, the number reads as heparin alone. Part of the inhibition comes from apixaban.

Read anti-Xa as heparin during an apixaban transition

A chromogenic anti-Xa method avoids clot-detection problems and still reads any factor Xa inhibition, so residual apixaban or rivaroxaban makes a heparin anti-Xa result appear falsely high. Each principle has its own interferences: turbidity for optical clot detection, weak clots for mechanical detection, and drugs or endogenous color for chromogenic assays.

Review Hemostasis instrumentation

Decision 3 of 3

Sam asks whether he can verify and release this result himself. What is the answer?

The certificate shows Sam was taught. It gives no evidence of how he performs on this analyzer.

Substituted course attendance for demonstrated performance

Attendance shows that the operator was taught the procedure. Competency for moderate- and high-complexity testing rests on six documented procedures, including direct observation, record review, blind or previously tested samples, and problem solving, so an attendance record leaves actual performance unassessed.

A checklist signed without observed evidence does not demonstrate competency. The six procedures need real observation and review.

A new analyzer needs training and documented competency before a person reports patient results. A qualified assessor documents Sam's assessment, and a competent colleague releases results in the meantime.

Review Training, competency, and continuing education

The clue that settles this case is what the anti-Xa assay reads. A heparin-calibrated chromogenic method counts all factor Xa inhibition, and apixaban was still present. The transition protocol and its comment keep the result from reading as heparin alone. Sam's certificate records training, and his competency still needs its documented assessment.

Keep

Sources checked