Through the present delta value check used in quality control programs is a powerful tool for detecting random errors in clinical chemistry analysis, it has some problems, such as missed true errors and delays in reporting time, because it also has the potential of showing erroneous positive results. Recently, new calculation methods for delta check with delta difference, delta percent change, rate difference, and rate percent change have been suggested by Lacher and Connelly (Clin Chem 34:1966-1970, 1988). Based on this new delta check method, we made the new criteria of which calculation method is applied to the clinical chemistry tests, i.e., the differential application of rate and delta check, and selectively applied the new method to 17 chemistry tests in order to solve the above problems. The applied criteria were the time dependence of the test item and the coefficient of variation of the absolute delta difference. Calcium, inorganic phosphorus, total protein, albumin, sodium, potassium, and chloride were classified as delta difference calculation method group; glucose and cholesterol as delta percent change group; creatinine, total and direct bilirubin as rate difference group; and urea nitrogen, uric acid, ALP, ALT, and AST as rate percent change group. With the previous criteria by Whitehurst et al. (Clin Chem 221:87-92) for 5045 specimens, the check-out rate was 47.8% (2,411 out of 5,045), and the positive predictive value was 0.41% (10 out of 2,411). For the new criteria, the check-out rate was 12.7% (621 out of 5,045), and the positive predictive value was 1.8% (nine out of 621).(ABSTRACT TRUNCATED AT 250 WORDS)

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We report a Korean family case of beta-thalassemia minor and Hb Queens. This is the first case report of Hb Queens in Korea. A 43-year-old male and his four family members had beta-thalassemia minor which is very rare in Korea. Incidentally, an alpha chain variant with a high isoelectric point was also found in two other family members without clinical problems and was finally identified as alpha 34 (B15) Leu-Arg or Hemoglobin Queens.

Additional key phrases: lipoprotein(a); ELISA; independent risk factorsLipoprotein(a) (Lp(a» is an LDL-like particle with a large glycoprotein called apo(a) attached to its apoB moiety through disulphide bonding. The structure of apo(a), which has multiple repeats of Kringle IV and one Kringle V, is strikingly similar to that of plasminogen. I Apo(a) consists of multiple isoforms ranging in size from about 400 000 to 700 000 Da. Many case-control studies showed that high Lp(a) directly correlates with premature coronary heart disease and is an independent risk factor for coronary artery disease (CAD).2 The distribution of Lp(a) concentration is highly skewed to the low concentration.J-' Lp(a) lipoprotein levels are higher in blacks than in whites, that is, racedependent. 3 Several methods for the quantitation of Lp(a) such as radial immunodiffusion, electroimmunoassay, radioimmunoassay, and immunonephelometry have been developed. 4The most commonly used technique is enzymelinked immunosorbent assay (ELISA),4,5 In the present study we quantitated the concentrations of Lp(a) using the competitive polyclonal ELISA method and evaluated Lp(a) as a risk factor of coronary artery disease in the Korean population. MATERIALS AND METHODSFor the reference value study, we measured serum Lp(a) levels in 250 healthy subjects. To investigate the association of levels of Lp(a), lipids and other lipoproteins with coronary artery disease, we selected 82 subjects who underwent coronary arteriography. These groups were classified into coronary artery disease (n =45) and Cath-control (n = 37) groups depending on whether any Correspondence: Professor lin Q Kim. 226 obstruction in the coronary artery was present or not. CAD groups were subclassified into 1-50%, 50-990/0 and 100% obstruction groups according to the degree of the obstruction in the coronary artery.We measured serum total cholesterol by a cholesterol oxidase enzymatic method, triglyceride by a glycerol oxidase enzymatic method, apolipoprotein A-I and B by immunonephelometric methods, HDL cholesterol by dextran sulphate-Mgf.l, precipitation, and LDL cholesterol by the Friedewald formula.We used Lp(a) antigen of narrow density-cut plasma (1' 050 -1. 080) and rabbit polyclonal anti-Lp(a) antibody donated from Dr E A Stein (Medical Research Laboratory, Cardiovascular Research Center, USA) which had no remarkable cross reactivity with plasminogen, and used OMEGA Lipid Fraction Control Serum (Lot No. 9V7751, Technicon Instruments Corporation) as a Lp(a) standard, After coating the 96 well microplates with Lp(a) antigen, we placed 50,.,.L of diluted standards, controls, and samples in a triplicate well, added 50,.,.L of diluted polyclonal rabbit anti-human Lp(a) to each well, then incubated for 2 h at 30°C. After washing four times, 100,.,.L conjugated antibody (alkaline phosphatase conjugated goat anti-rabbit immunoglobulin-Sigma A8025) diluted 400-fold was added to each well and incubated for 1 h at 30°C. The plates were again washed four times. Then l00,.,.L of freshly prepa...

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