The number reported under Hemolysis on our chemistry panels is a semi-quantitative measurement of the concentration of free hemoglobin in mg/dL.
Free hemoglobin in the sample has little or no affect on most assays unless the level is very high (>300 hemolytic index). Cornell University provides guidelines on how hemolysis affects sample results. These guidelines are derived from manafacturer's recommendations and is based on data from spiking human samples with hemoglobin. These values may not apply to samples from animals and there are important species differences (for example, a high potassium is expected in hemolyzed samples from horses because potassium concentrations in equine erythrocytes are far higher than in serum). These guidelines should always be used in conjunction with clinical signs and knowledge of the underlying disease processes as guides for interpreting laboratory data and determining the accuracy of reported laboratory results.In general, marked hemolysis produces misleading results in the following analytes:
- Can increase: Phosphate,
potassium (horses, pigs, Japanese breed dogs (e.g. Akitas), some cows
and sheep), CK, AST, LDH, uric acid, and magnesium.
- Can decrease: alkaline phosphatase, amylase, and GGT.
| Hemolysis index | Gross appearance |
|---|---|
| <20 | No hemolysis |
| 20-100 | slightly hemolyzed (pink tinged) |
| 100-300 | moderately hemolyzed (red) |
| >300 | markedly hemolyzed (dark red) |
A visual representation of how the hemolytic index (HI) correlates to visual hemolysis is shown in the image below.
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