Managing Specimen Integrity

Evaluates specimen adequacy and rejection criteria with pre-analytical quality documentation.

Why This Skill Exists

Pre-analytical errors account for 46-68% of all laboratory errors, and specimen integrity failures are the leading cause. A hemolyzed potassium specimen, a clotted coagulation tube, an unlabeled surgical specimen, or an improperly transported microbiology culture can each produce misleading results that drive incorrect clinical decisions. The economic cost is substantial: recollection disrupts clinical workflows, delays diagnosis, and in some cases (neonatal, oncology, difficult-access patients) recollection may be impossible or harmful.

CLIA 42 CFR 493.1242 requires laboratories to establish specimen submission and handling instructions and define criteria for specimen rejection. CAP accreditation (GEN.40490-40530 series) mandates documented acceptance/rejection criteria, specimen labeling requirements (two patient identifiers), and processes for managing non-conforming specimens. The Joint Commission patient safety goals reinforce two-identifier specimen labeling. This skill provides a systematic framework for evaluating specimen integrity and managing pre-analytical quality.

Checkpoint A: Pre-Draft Intake (Mandatory)

Specimen type — Blood (tube type), urine, tissue, body fluid, swab, or other? Default: blood specimen.
Test(s) ordered — What analytes are requested? Different tests have different integrity requirements. Default: comprehensive metabolic panel.
Issue identified — Hemolysis, lipemia, icterus, clotting, underfill, mislabel, wrong tube, delayed transport, temperature excursion, or other? Default: hemolysis.
Patient context — Difficult draw (neonatal, dialysis, oncology), repeated collection issue, stat/urgent request? Default: routine adult.
Collection site — Was the specimen drawn from an IV line, port, or direct venipuncture? Default: direct venipuncture.
Time since collection — How long has the specimen been in transit or storage? Default: < 2 hours.
Recollection feasibility — Can a new specimen be obtained without significant burden? Default: yes.

Documents to Request

Specimen requisition form with two identifiers
Collection time and collector identity
Transport conditions (temperature, time in transit)
Tube type and anticoagulant verification
Hemolysis/lipemia/icterus index from analyzer (if quantified)
Institutional specimen acceptance/rejection criteria policy
Test-specific specimen requirements (stability, tube type, volume)
Non-conforming specimen log

Step 1: Specimen Identification and Labeling Verification

Verify specimen labeling per CAP and Joint Commission requirements:

Minimum labeling requirements (CAP GEN.40490):

Two unique patient identifiers (name + DOB, name + MRN, or equivalent)
Date of collection
Time of collection (required for time-sensitive analytes)
Collector identification
Specimen source/type (for non-blood specimens)

Rejection criteria for labeling deficiencies:

| Deficiency | Action | |---|---| | No label on specimen | REJECT — no exceptions. Specimen cannot be relabeled after leaving the patient. | | One identifier only | REJECT — recollect. Two identifiers are non-negotiable per Joint Commission NPSG. | | Label on container but not on tube | REJECT — the tube itself must be labeled, not just an accompanying form. | | Discrepancy between label and requisition | HOLD — contact collector for resolution before processing. | | Illegible label | HOLD — contact collector for verification; reject if unresolvable. |

Exception: Surgical pathology and cytology specimens may have a reconciliation process per CAP ANP.11700, but the two-identifier requirement still applies.

Step 2: Specimen Condition Assessment

Evaluate the physical condition of the specimen:

Hemolysis Index (Chemistry Analyzers)

| H-Index | Hemolysis Level | Affected Analytes | Action | |---|---|---|---| | H < 50 | None/slight | None significantly | Process normally | | H 50-100 | Mild | Potassium (+), LDH (+), AST (+), iron (+) | Report with comment for mildly affected analytes | | H 100-200 | Moderate | K, LDH, AST, iron, total bilirubin, phosphorus | Reject affected analytes; report unaffected | | H > 200 | Gross | Most chemistry analytes affected | Reject specimen; recollect |

Lipemia Index

| L-Index | Lipemia Level | Affected Analytes | Action | |---|---|---|---| | L < 150 | None/slight | None significantly | Process normally | | L 150-300 | Moderate | Electrolytes (pseudohyponatremia), some enzymes | Report with comment | | L > 300 | Gross | Many analytes affected by light scattering | Ultracentrifuge or reject |

Icterus Index

| I-Index | Icterus Level | Affected Analytes | Action | |---|---|---|---| | I < 20 | None/slight | None significantly | Process normally | | I 20-40 | Moderate | Creatinine (Jaffe method), some enzymatic assays | Report with comment | | I > 40 | Marked | Multiple analytes affected | Report with interference note |

Step 3: Tube Type and Volume Verification

Confirm correct tube type and adequate fill volume:

Common tube types and requirements:

| Tube Color (Cap) | Additive | Tests | Minimum Fill | |---|---|---|---| | Light blue (citrate) | 3.2% sodium citrate | PT, PTT, fibrinogen, coag factors | 90% fill (9:1 blood:citrate ratio); underfill produces falsely prolonged results | | Lavender (EDTA) | K2EDTA or K3EDTA | CBC, differential, reticulocyte, HbA1c | Minimum 0.5 mL for CBC | | Green (heparin) | Lithium heparin or sodium heparin | Stat chemistry, ammonia | Per tube manufacturer | | Gold/red (SST/no additive) | Clot activator +/- gel | Routine chemistry, serology, drug levels | Allow 30 min clotting before centrifugation | | Gray (NaF/oxalate) | Sodium fluoride/potassium oxalate | Glucose, lactate | Per tube manufacturer |

Rejection criteria for tube/volume issues:

| Issue | Action | |---|---| | Citrate tube < 90% filled | REJECT for coagulation tests. Insufficient fill alters the blood:citrate ratio. | | Clotted EDTA specimen | REJECT for CBC. Platelet count will be falsely low. | | Wrong tube type for test | REJECT — do not attempt to process. | | Specimen drawn from IV line without discard | REJECT — risk of dilution or contamination with IV fluids. |

Step 4: Stability and Transport Assessment

Evaluate whether specimen stability requirements were met:

Critical stability windows:

| Analyte/Test | Room Temp Stability | Refrigerated Stability | Special Requirements | |---|---|---|---| | Potassium | 4 hours (separate from cells) | 24 hours (after separation) | Must centrifuge within 1 hour; pseudohyperkalemia if delayed | | Glucose (no NaF) | 30 minutes | 2 hours | Glycolysis reduces glucose ~7%/hour at room temp | | Ammonia | 15 minutes on ice | 15 minutes on ice | Must be transported on ice and centrifuged immediately | | Blood gas (ABG) | 15 minutes (plastic syringe) | 30 minutes (glass syringe, ice) | Air bubbles invalidate pO2/pCO2 | | Lactic acid | 15 minutes on ice | 15 minutes on ice | Tourniquet time and fist clenching cause false elevation | | Coagulation (PT, PTT) | 4 hours at RT (uncentrifuged) | 24 hours (centrifuged, frozen) | Do not refrigerate uncentrifuged citrate tubes | | CSF cell count | 1 hour | 1 hour | WBCs lyse rapidly; process stat |

Step 5: Non-Conforming Specimen Management and Documentation

When a specimen is rejected or has quality issues, follow a structured process:

Document the issue: Record the specific non-conformance (hemolysis, clot, mislabel, etc.) in the LIS.
Notify the collector/ordering provider: Per institutional policy, communicate the rejection reason and recollection instructions.
Partial reporting: When possible, report unaffected analytes from the specimen and reject only those analytes affected by the integrity issue. Add interpretive comments.
Log the non-conformance: Enter into the non-conforming specimen tracking system for trending.
Trend analysis: Review non-conformance data monthly. Identify patterns by collector, unit, specimen type, or time of day. Target QI interventions to reduce the most common and impactful errors.
Education and feedback: Provide targeted education to collection staff when trends are identified. Document training and re-competency assessment.

Checkpoint B: Post-Draft Alignment (Mandatory)

Was specimen labeling verified against the two-identifier requirement before any testing?
Were hemolysis, lipemia, and icterus indices quantified and applied to analyte-specific rejection criteria?
Was tube type confirmed as correct for all ordered tests?
Were stability requirements assessed based on collection time and transport conditions?
Was the non-conforming specimen documented in the tracking system with collector notification?

Quality Audit

[ ] Two patient identifiers verified on specimen label
[ ] Collection date, time, and collector identity documented
[ ] Hemolysis/lipemia/icterus index quantified by analyzer
[ ] Analyte-specific rejection thresholds applied (not blanket rejection)
[ ] Tube type correct for all ordered tests
[ ] Citrate tube fill volume verified (>= 90% for coagulation)
[ ] Specimen transported within stability requirements
[ ] Temperature-sensitive specimens transported on ice when required
[ ] Non-conforming specimen logged with specific rejection reason
[ ] Collector/provider notified of rejection with recollection instructions
[ ] Monthly trending of non-conformance data performed
[ ] QI interventions documented for identified trends
[ ] Institutional acceptance/rejection criteria policy current and accessible
[ ] Staff competency for specimen assessment documented annually

Guidelines

Never process an unlabeled specimen regardless of urgency — this is a non-negotiable patient safety requirement per CAP and Joint Commission
Quantify hemolysis, lipemia, and icterus using the analyzer's serum index system rather than visual estimation; visual assessment is unreliable and not auditable
Apply analyte-specific rejection thresholds rather than blanket specimen rejection; many analytes are unaffected by mild hemolysis, and rejecting the entire panel wastes clinical resources
For citrate tubes (coagulation testing), reject any tube less than 90% filled; the altered blood-to-citrate ratio produces unreliable PT and PTT results regardless of how "close" the fill appears
Separate serum/plasma from cells within 1 hour of collection for potassium and other cell-sensitive analytes; delayed separation is the most common cause of pseudohyperkalemia
Track non-conforming specimens by collector, unit, and specimen type; use the data for targeted quality improvement rather than punitive action
When recollection is impossible or poses significant patient burden (neonatal, difficult access), consult with the laboratory director about reporting with appropriate qualifiers and comments
Review and update institutional acceptance/rejection criteria at least annually and whenever new tests or specimen types are introduced