Evaluates specimen adequacy and rejection criteria with pre-analytical quality documentation. Use when assessing specimen quality, documenting rejection reasons, or managing pre-analytical errors.
Evaluates specimen adequacy and rejection criteria with pre-analytical quality documentation.
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.
Verify specimen labeling per CAP and Joint Commission requirements:
Minimum labeling requirements (CAP GEN.40490):
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.
Evaluate the physical condition of the specimen:
| 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 |
| 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 |
| 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 |
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. |
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 |
When a specimen is rejected or has quality issues, follow a structured process: