The measurement of fractionated bilirubin by Ektachem film slides. Method validation and comparison of conjugated bilirubin measurements with direct bilirubin in obstructive and hepatocellular jaundice.

The authors evaluated the Kodak Ektachem Slides for total, "direct," conjugated, unconjugated, and albumin-bound ("delta") bilirubin. For various concentrations of control material, the precision (CV) within- and between-day ranged from 1.7 to 2.4% (2.8-6.6%) for total bilirubin, 0.8-4.2% (1.6-11.5%) for unconjugated bilirubin, and 1.6-9.5% (2.6-20.7%) for conjugated bilirubin. The Ektachem total and "direct" bilirubin assays demonstrated excellent correlation with the Jendrassik and Grof procedure; a 30% difference was observed, however, between absolute numbers with the two direct bilirubin methods. We found the measurement of true conjugated bilirubin by the Kodak Method to be superior to the measurement of "direct" bilirubin in following the response to treatment of various hepatic disorders manifested by extrahepatic and intrahepatic biliary obstruction.

Multilayered film analysis: evaluation of ammonia and creatinine slides.

We evaluated the Kodak Ektachem multilayer ammonia and creatinine slides. For various concentrations of control material the precision (CV) within- and (between-day) ranged from 0.8 to 7.8% (4.4-9.0%) for ammonia, and 1.9-25.1% (3.6-13.9%) for creatinine. A number of commercial control fluids were unacceptable choices due to the presence of elevated endogenous ammonia levels. For both analytes, analytical recovery was in the range of 100 to 108%. Comparison with the Jaffe reaction demonstrated good correlation for creatinine, and linearity was judged acceptable for both analytes. For ammonia, serum values were nearly double those of paired plasma samples. Plasma and serum samples, therefore, cannot be used interchangeably. No serum versus plasma differences were observed for creatinine.

Multilayer film analysis: evaluation of ion-selective electrolyte slides.

We evaluated the Kodak Ektachem multilayer ion-selective electrolyte slides. For various types and concentrations of control material the precision (CV) within- and between-day ranged from 0.5 to 1.3% (1.7-2.1%) for sodium, 1.2 to 2.2% (2.7-2.9%) for potassium, 2.9 to 4.6% (5.9-6.7%) for carbon dioxide, and 0.7 to 1.6% (1.3-1.4%) for chloride. For all these analytes, analytical recovery was about 100%, except in the supra-physiological ranges, for which carbon dioxide recovery was about 110-120%. Either serum or heparin-treated plasma can be used, interchangeably, for analysis; use of serum treated with lithium iodoacetate is unacceptable. Comparisons with results by continuous-flow procedures demonstrated good correlation for sodium, potassium, and chloride; carbon dioxide comparisons indicate an Ektachem calibrator change may be required. Abnormally low protein concentrations or lipemia had no observed effects on results for electrolytes. Abnormally high protein concentrations affect sodium results slightly (approximately 5 mmol/L).

Monoclonal evolution of angioimmunoblastic lymphadenopathy.

A patient with angioimmunoblastic lymphadenopathy diagnosed on initial lymph node biopsy was found on rebiopsy two months later to have immunoblastic lymphoma as well. At presentation she had polyclonal hypergammaglobulinemia with polyclonal (kappa and lambda light chains) immunoblasts demonstrated by the immunoperoxidase stain. During the course of her illness, a monoclonal IgM kappa gammaglobulinemia developed, accompanied by monoclonal (kappa light chains only) immunoblasts demonstrated by the immunoperoxidase method. These findings were unique in that lymphomatous transformation and clinical deterioration are shown to be accompanied by a monoclonal evolution of immunoblasts. This constitutes further evidence for the heterogeneous nature of patients who have angioimmunoblastic lymphadenopathy and the malignant potential of this disease.

The multilayered film analyzer: glucose in serum, plasma, cerebrospinal fluid, and urine; and urea nitrogen in serum and plasma.

Some basic laboratory performance criteria were studied for the Eastman Kodak glucose and urea nitrogen analyzer. Serum, plasma, urine, and cerebrospinal fluid were tested. Precision, both "within-day" and "between-day," for both analytes was less than 2.2% (CV). Both analytes demonstrated linearity, with about 100% recovery of added substrates. Comparisons with continuous-flow procedures demonstrated good correlation. A variety of sera and plasmas can be used for glucose analysis; oxalate--fluoride-treated plasma is unacceptable for use in analysis for urea nitrogen. We saw no effects on glucose or urea nitrogen analysis from hemolysis, lipemia, icterus, some common drugs, ammonia, or abnormally high protein concentrations. Minimum amounts detectable were: glucose (serum) 104 mg/L; glucose (cerebrospinal fluid) 100 mg/L; and urea nitrogen (serum) 21 mg/L. Calibration procedures are discussed for protein-based and aqueous samples.

Radioimmunoassay of serum myoglobin: evaluation and modification of a commercial kit and assessment of its usefulness for detecting acute myocardial infarction.

We evaluated a modified procedure for a commercially available myoglobin radioimmunoassay kit (Nuclear Medical Systems). Within-run and run-to-run precision was acceptable. Normal ranges were established and paralelism studies performed. Clinical usefulness was assessed in 100 consecutive patients admitted to our coronary-care facility. The determinations were done daily, along with creatine kinase and its isoenzymes, and lactate dehydrogenase and its isoenzymes. Fifty of the 100 patients ultimately were shown to have had acute myocardial infarction. Myoglobinemia was present in most of the patients with acute myocardial infarction, but information on its presence was less usefull clinically than was detection of creatine kinase isoenzyme MB.

The significance of the MB isoenzyme in patients with acute cardiovascular disease with a normal or borderline total CPK activity.

CPK MB isoenzymes were qualitatively identified using an electrophoresis method in 166 patients with acute cardiovascular disease during a six month period. Forty-three had total CPK activity in the normal or borderline range (0--75 U/Liter at the time the MB isoenzyme was first identified. Fifteen of these patients were diagnosed as having had a new acute myocardinal infarction (Group I) and another 15 as having had an old myocardial infarction (Group II). Diagnosis was based on electrocardiographic changes or autopsy findings. The remaining 13 patients were classified as "ischemic heart disease" (Group III) in the absence of strict electrocardiographic criteria or autopsy evidence of myocardial infarction. Nine of the 15 patients in Group I subsequently had elevations of their total CPK activity above 75 U/L. In contrast the total CPK activity of only one patient from Group II and Group III subsequently exceeded 75 U/liter. All 43 patients had evidence of cardiovascular disease. Our findings suggest that the detection of MB isoenzyme in the presence of a normal total CPK activity is a significant laboratory finding and is indicative of cardiac myofiber injury.

A comparative study of five commercial reagents for the Coulter Model S: a proposed method for reagent evaluation.

A comparative study of five competitive commercial reagents for the Coulter Model S was performed jointly by two large, busy hospital laboratories with active quality control programs. Both laboratories, independently using the same reagent systems, studied 20 consecutive blood samples from patients from their own respective hospital for 20 days. Data from both laboratories were analyzed by standard and nonstandard statistical methods, and the results from both laboratories were compared. Although all reagent systems performed reasonably well in a clinical setting, highly significant statistical differences in their precisions were demonstrated by using univariate and multivariate techniques. The statistical method developed in this study can be applied to other systematic investigations that compare reagent systems.