Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (823 page)

   Improperly filled test tubes or the use of different anticoagulants than recommended (3.2% sodium citrate as provided in blue top tubes).

   Improperly stored plasma.

   Hyperlipidemic, hemolyzed, or icteric blood may affect the results with some coagulation instruments.

   Contamination with heparin or dilution of the collected blood if indwelling catheters are used.

CLOTTING TIME (LEE-WHITE CLOTTING TIME)
*

The clotting time is characterized by low sensitivity and poor standardization. It is of only historical interest and is no longer in use.

COBALT

   Definition

   Cobalt is an essential trace element and an integral part of cyanocobalamin (vitamin B
₁₂
). It is also used industrially in the manufacture of high-strength alloys used for cutting/drilling tools, in the semiconductor industry, and as a pigment. Acutely toxic in large doses and in cumulative long-term low-level exposure from cobalt processing plants, hard metal industry, diamond polishing, and ceramic industry.

   Chronic exposure to inorganic cobalt salts, either by ingestion or by inhalation of dust, causes respiratory distress, dyspnea, and pneumoconiosis or can lead to cardiomyopathy. Inorganic cobalt can induce hemoglobin synthesis, as well as hypertriglyceridemia and hypercholesterolemia.

   Cobalt is quickly cleared through the kidneys, and urine cobalt measurements are a useful indicator of recent exposure.

   
Normal range:
Less than 1 μg/L.

   Use

   Assessing occupational and environmental cobalt exposure

   Detection of cobalt toxicity

   Monitoring metallic implants wear