What each step actually requires

The order and requisition step has specific content requirements even before a specimen exists. CLIA requires that a requisition solicit patient identification, the requested test, specimen source when appropriate, collection date or time when appropriate, and information needed for accurate testing and interpretation, and requires accurate transcription into the laboratory information system when requisition information is entered there (42cfr-493-1241). A missing collection time or an ambiguous test name at this step can propagate through the whole process without ever triggering an analyzer error.

Specimen integrity is decided before the analyzer runs. A specimen that is hemolyzed, clotted, short filled, incorrectly collected, or transported outside its validated conditions may not yield a result suitable for release, and this is a preexamination judgment documented at receipt (42cfr-493-1242; clsi-pre01-ed1). Hemolysis matters specifically for potassium: erythrocytes hold far more potassium than the surrounding plasma, so lysis during or after collection can release intracellular potassium into the specimen and spuriously raise the measured value. The size of that bias depends on the specimen, the method, and the degree of hemolysis, so it cannot be corrected with a fixed formula (lippi-2019). An analyzer that reports a hemolysis index is flagging the specimen, not diagnosing the cause of hemolysis.

Before an unmodified FDA-cleared method reports patient results, the laboratory must verify its accuracy, precision, reportable range, and the suitability of the manufacturer's reference interval for its own patient population; a modified or laboratory-developed method requires establishing those performance specifications from scratch (42cfr-493-1253). Control procedures, set from those verified specifications, monitor accuracy and precision across the whole analytic process and are meant to catch both an immediate shift and a slow drift over time; a complete reagent change, major preventive maintenance, or replacement of a critical part requires control testing again before patient testing resumes (42cfr-493-1256). None of this is a one-time setup step. It is maintained continuously and re-verified whenever something that could affect it changes, including autoverification logic, which CAP requires to be revalidated whenever a change to the system could affect that logic (cap-gen43875).

A reference interval is a laboratory- and population-specific interpretive context, not a clinical decision limit and not a diagnosis (clsi-ep28-a3c; 42cfr-493-1291). The laboratory must make its determined reference intervals available to the requester, along with method, performance, and interference information on request (42cfr-493-1291). Imminently life-threatening, panic, or alert results require immediate alerting of the requester and, when applicable, the person using the result (42cfr-493-1291). No numeric hemolysis-index cutoff, delta-check threshold, critical-value limit, or turnaround-time target is stated here, because those figures are analyzer-, assay-, and population-specific and require local validation rather than a transferable universal number (ditoro-2022).

Treat every flag, whether it is a hemolysis index, a delta check, or a critical value, as a prompt to check the specimen and the record against local policy, not as a number to explain away.