The essential role of information management in point-of-care/critical care testing.

Laboratory medicine is undergoing tremendous change in recent years driven primarily by technology, regulations, reimbursement, and market forces. In this paradigm shift, the laboratory is under tremendous pressure to adapt to new requirements for critical care testing. Indeed, laboratories have entered the information age where chemical data is being extracted from specimens in totally automated fashion. In the past, laboratory data has played a more historical role in the care of critically ill patients, arriving at the bedside too late to be of significant use in the active, ongoing care of the patient. However, today's physicians taking care of critically ill patients now require that laboratory results are made available in real-time and, if possible, at the patient's point-of-care. Many new testing point-of-care testing (POCT) devices have been developed to address this need however often laboratories implement such distributed devices with little or no attention to the information technology requirements. In fact, as little as 10% of point-of-care testing is actually managed by the central laboratory computer hence critically importance results are not found on the patient's electronic medical record. In addition, the billing and management data for point-of-care testing is often handled manually with no plans to interface point-of-care devices to the laboratory billing and management systems. Because of recent improvements of information handling and interface capability, such shortcomings in data management are no longer acceptable. Indeed, the demands for laboratories to utilize information technology are such that those laboratories with no overall plan for data management of critical care testing will probably not survive this market-driven paradigm. We present a discussion of the various approaches to computerization of point-of-care testing including the advantages and the disadvantages of each approach.

Staging of the baboon response to group A streptococci administered intramuscularly: a descriptive study of the clinical symptoms and clinical chemical response patterns.

Group A streptococcal infections, ranging from necrotizing fasciitis and myositis to toxic shock syndrome, have increased over the last 10 years. We developed the first primate model of necrotizing fasciitis and myositis. Thirteen baboons were inoculated intramuscularly with group A streptococci (GAS). Eleven animals survived for > or = 11 days before sacrifice, and two animals died within 2 days. The site of inoculation of the survivors exhibited an intense neutrophilic influx (stage I), followed by a lymphoplasmacytic influx (stages II and III). This was accompanied by the appearance of markers of an acute and then a chronic systemic inflammatory response. In contrast, the site of inoculation of the two nonsurvivors exhibited intravascular aggregates of neutrophils at its margin with no influx of neutrophils and with extensive bacterial colonization. We conclude that GAS inoculation induces a local and systemic acute neutrophilia followed by a chronic lymphoplasmacytic response; failure, initially, of neutrophilic influx into the site of inoculation predisposes to systemic GAS sepsis and death; and this three-stage primate model approximates the human disease.

The determination and interpretation of reference intervals for multichannel serum chemistry tests.

BACKGROUND: When interpreting the results of clinical chemistry tests, physicians rely heavily on the reference intervals provided by the laboratory. It is assumed that these reference intervals are calculated from the results of tests done on healthy individuals, and, except when noted, apply to people of both genders and any age, race, or body build. While analyzing data from a large screening project, we had reason to question these assumptions. METHODS: The results of 20 serum chemistry tests performed on 8818 members of a state health insurance plan were analyzed. Subgroups were defined according to age, race, sex, and body mass index. A very healthy subgroup (n = 270) was also defined using a written questionnaire and the Duke Health Profile. Reference intervals for the results of each test calculated from the entire group and each subgroup were compared with those recommended by the laboratory that performed the tests and with each other. Telephone calls were made to four different clinical laboratories to determine how reference intervals are set, and standard recommendations and the relevant literature were reviewed. RESULTS: The results from our study population differed significantly from laboratory recommendations on 29 of the 39 reference limits examined, at least seven of which appeared to be clinically important. In the subpopulation comparisons, "healthy" compared with everyone else, old (> or = 75 years) compared with young, high (> or = 27.1) compared with low body mass index (BMI), and white compared with nonwhite, 2, 11, 10, and 0 limits differed, respectively. None of the contacted laboratories were following published recommendations for setting reference intervals for clinical chemistries. The methods used by the laboratories included acceptance of the intervals recommended by manufacturers of test equipment, analyses of all test results from the laboratory over time, and testing of employee volunteers. CONCLUSIONS: Physicians should recognize when interpreting serum chemistry test results that the reference intervals provided may not have been determined properly. Clinical laboratories should more closely follow standard guidelines when setting reference intervals and provide more information to physicians regarding the population used to set them. Efforts should be made to provide appropriate intervals for patients of different body mass index and age.

Cell proliferation in the developing human kidney.

In a previous study, utilizing antibodies to proliferating cell nuclear antigen (PCNA), we determined the proliferation index (PI) (percentage of PCNA-positive cells) of intrinsic renal cell populations in the normal adult and pediatric kidney. We have found that the PI in both adult and pediatric kidneys was very low (below 0.5 in all examined cell populations). In our present study, we investigated cell proliferation in the developing human kidney with an antibody to PCNA. Histologically normal kidneys were collected from 25 fetuses (spontaneous abortions and stillborns) ranging from 10 wk of gestation to term. Immature mesenchyme (blastema), immature early tubules, ampulla of ureteric bud, proximal tubules, Tamm-Horsfall protein (THP)-positive tubules, distal tubules, collecting ducts, and glomeruli were evaluated separately. The PI for each cell population was calculated. The PI of immature early tubules remains high (33-43) throughout embryonic life. The PI of blastemal cells is initially similarly high, but gradually decreases starting from the second trimester. The PI of THP-positive tubules, distal tubules, collecting ducts, and glomeruli starts out relatively high (5.9, 8.6, 6.0, and 12.4, respectively) and decreases gradually as term approaches (1.8, 1.3, 1.2, and 1.4, respectively). Interestingly, as soon as proximal tubules become differentiated (appearance of light microscopic features of proximal tubular epithelium with TP lectin positive brush border), their PI becomes very low (below 1) irrespective of the age of the kidney. This is the first quantitative study to show changes of the PI in various renal cell populations during human nephrogenesis. These changes in the PI relate to the stage of differentiation of the developing nephron segments.

Decision-making laboratory computer systems as essential tools for achievement of total quality.

Areas other than the analytical process should be the focus of concern about quality issues in the laboratory because nearly 95% of errors occur at the nonanalytical front and back ends of the testing process. Until now, computer systems have been designed to handle the more predictable aspects of laboratory testing, necessitating that the infrequent and unpredictable data events be handled by manual systems. The manual systems are termed "workarounds" and indeed, because they occur sporadically, they are frequently not handled predictably. Here, I describe and give examples of an expert laboratory computer system that can be designed to handle both predictable and unpredictable data events without the use of manual workarounds. This expert system works in concert with a dynamic database allowing such data events to be detected in real time and handled predictably, thus providing a tool to address quality assurance issues throughout the testing process. The system performs up to 31 separate actions or tasks based on data events that in the past were handled by human workarounds.

Mast cells in acute cellular rejection of human renal allografts.

Mast cells (MCs), few in the normal kidney, are found in increased number in the renal parenchyma in diseases associated with persistent chronic inflammation. MCs are not easily identified in routinely processed archival tissue sections with histochemical stains. A more reliable method of detection was provided with the introduction of MC tryptase-specific monoclonal antibodies. To determine the possible role of MCs in renal allograft rejection, we studied 28 biopsy specimens from renal allografts that had been in place for various lengths of time (from 3 days to 40 months) in patients whose primary diagnosis was acute interstitial rejection; the specimens were associated with varying degrees of interstitial fibrosis, edema, and hemorrhage. The specimens were graded on a semiquantitative scale (from 0 to 3+) for the severity of rejection, the degree of interstitial fibrosis, interstitial edema, and interstitial hemorrhage. Eosinophils, plasma cells, and MCs were quantitatively evaluated in these biopsy specimens. MCs were detected by use of a commercially available anti-MC tryptase monoclonal antibody, which proved to be an excellent tool to detect MCs in routinely processed paraffin sections. A positive correlation was found between the number of MCs and the time since transplantation (R = 0.841, P < 0.005) and between the number of MCs and the severity of interstitial fibrosis (R = 0.489, P < 0.005), as well as with interstitial edema (R = 0.517, P < 0.005). MCs were increased in number in patients with moderate (n = 18; mean, 18.00 MCs per 10 high power fields [HPFs]) and severe (n = 5; mean, 12.20 MCs per 10 HPFs) acute rejection compared with patients with mild (n = 5; mean, 2.44 MCs per 10 HPFs) acute rejection and normal kidneys (n = 6; mean, 1.75 MCs per 10 HPFs). These results suggested that MCs might play a role in the process of acute rejection of renal allografts and in the development of interstitial fibrosis.

Human acute tubular necrosis: a lectin and immunohistochemical study.

To determine the nephron segment distribution of tubular epithelial damage and regeneration and the proliferative activity of various nephron segments in human acute tubular necrosis (ATN) with an antibody to proliferating cell nuclear antigen (PCNA) and to compare the findings in native kidneys with ATN with those in transplant kidneys with ATN, archival tissues from 12 native and 21 transplant kidney biopsy specimens and nine transplant nephrectomy specimens were collected that all showed obvious morphological signs of ATN. Nineteen patients with transplant kidneys with ATN were immunosuppressed with cyclosporine and 11 were immunosuppressed with prednisone and azathioprine. There was a predominance of "regenerating" tubules (tubules with thin epithelium) in the distal nephron in native kidneys with ATN; in the transplant kidneys this was less conspicuous. The number of Tamm-Horsfall protein (THP)-positive tubules was decreased in all kidneys with ATN compared with normal human kidneys. In contrast, the number of THP-positive casts was much higher in all kidneys with ATN than in the normal kidneys. In transplant kidneys with ATN the number of THP-positive casts was substantially lower than in native kidneys with ATN. The macula densa appears to maintain its morphological integrity in kidneys with ATN. Both regenerating and normal appearing tubules expressed vimentin and HLA-DR. The proliferation index (PI; ie, percentage of PCNA-positive nuclei) of the renal tubular epithelium in normal control kidneys varied between 0.22 and 0.33, depending on the tubule segment. The highest PI was noted in the transplant kidneys with ATN not treated with cyclosporine (8.0), followed by the native kidneys with ATN (4.4) and the transplant kidneys with ATN treated with cyclosporine (4.3). We did not find any significant difference in the PI between the regenerating (5.0) and normal appearing (5.6) tubules. Proximal tubules (8.7) showed significantly higher PI values than distal tubules (3.5) in transplant kidneys with ATN. Our results show substantial differences between native kidneys and transplant kidneys with ATN. Tubular epithelial cell proliferation in human ATN is prominent and appears to correlate with the severity of ATN. Light microscopically normal appearing tubules and regenerating tubules participate equally in the regeneration of injured tubules. Cyclosporine may have an inhibitory effect on cell regeneration (proliferation) in human transplant kidneys with ATN.

Proliferative activity of cyst epithelium in human renal cystic diseases.

Increased proliferative activity of the renal tubular epithelium is thought to be a prerequisite for renal cyst formation by many investigators. However, in humans, the exact in vivo proliferation rate of epithelial cells lining these cysts is not known. In this study, which used immunohistochemical methods with an antibody to proliferating cell nuclear antigen (PCNA), the proliferation index (PI) (percentage of PCNA positive cell nuclei among epithelial cells lining the renal cysts) was determined in 10 cases of autosomal dominant polycystic kidney disease (ADPKD), 8 cases of autosomal recessive polycystic kidney disease (ARPKD), and 8 cases of acquired cystic kidney disease (ACKD). Cysts with proximal and distal nephron phenotype and cysts with markedly thickened basement membranes, as well as cysts lined by atrophic (flattened), "regular" (cuboidal or cylindrical), and hyperplastic epithelium, were evaluated separately. The overall PI of cyst epithelium (excluding hyperplastic cysts) was 2.58 in ADPKD, was 10.5 in ARPKD, and was 3.61 in ACKD. Overall, there were only minor differences in the PI between the various types of cysts. Cysts with hyperplastic epithelium in ACKD (unlike in ADPKD) showed a high PI (9.1). For comparison, the PI of two renal cell carcinomas occurring in two ACKD cases was also determined (13.70 and 8.67%). The PI of tubular epithelium in normal kidneys was only 0.22 to 0.33%, depending on the tubule segment. In contrast, in polycystic kidneys, those noncystic segments of the nephron from which the cysts are thought to originate (distal nephron (specifically collecting duct)) in ARPKD, primarily distal in ADPKD, proximal and distal in ACKD, had PI values similar to those of the cyst epithelium.(ABSTRACT TRUNCATED AT 400 WORDS)

Proliferative activity of intrinsic cell populations in the normal human kidney.

The proliferative activity of various normal human renal cell populations is unknown. Recently, antibodies to cell proliferation-associated nuclear proteins, such as proliferating cell nuclear antigen (PCNA) and KI-67, which are applicable to archival paraffin sections, became available. With antibodies to PCNA and Ki-67 after microwave pretreatment of the paraffin sections, the proliferation indexes (ratio of positive nuclei with PCNA and Ki-67 antibodies/all nuclei counted x 100, i.e. percentage of positive cells) of 12 different intrinsic renal cell populations in 20 normal human kidneys have been determined. The following proliferation indexes (percentages of positive cells) were found with the PCNA and the Ki-67 antibodies, respectively: proximal tubular epithelium, 0.22, 0.24; thin limb of Henle, 0.29, 0.30; thick ascending limb of Henle, 0.32, 0.29; distal tubular epithelium (distal convoluted tubules and cortical collecting ducts, 0.33, 0.44; medullary collecting ducts, 0.32, 0.3; glomerular mesangial cells, 0.07, 0.12; glomerular visceral epithelial cells, 0.04, 0.08; glomerular parietal epithelial cells, 0.07, 0.1; glomerular capillary endothelium, 0.42, 0.47; peritubular capillary endothelial cells, 0.38, 0.43; endothelium of large intrarenal vessels (arteries and veins), 0.09, 0.12. Thus, normally capillary endothelium (glomerular and peritubular) appears to have the highest proliferation index in the human kidney by these techniques. These results indicate major variation in the proliferative activity of normal human renal cell populations, along with a significant correlation between PCNA and Ki-67 staining. Furthermore, this study provides normal values for the proliferative activity of different human renal cell populations.(ABSTRACT TRUNCATED AT 250 WORDS)

Tubular atrophy in the end-stage kidney: a lectin and immunohistochemical study.

Atrophic tubules in end-stage renal disease (ESRD) may have various morphologic appearances: some show microscopic features of "classic" atrophic tubules (thick, wrinkled tubular basement membrane and simplified epithelium), others show "thyroidization" (round tubules with simplified epithelium and casts), and many have the appearance of "endocrine" tubules (small tubules with narrow lumina, clear cells, and relatively thin basement membranes). Other tubules in ESRD may be enlarged and dilated with hypertrophic cells ("super" tubules). The exact segment of the nephron from which these tubules arise in ESRD has not been well studied. We examined paraffin sections of 28 end-stage kidneys with a panel of nephron-segment-specific renal epithelial markers (proximal nephron markers: Tetragonolobus purpureas and Phaseolus vulgaris erythroagglutinin lectins; distal nephron markers: antibodies to epithelial membrane antigen, low molecular weight cytokeratin [AE1/AE3], the lectin Arachis hypogaea, and an antibody to Tamm-Horsfall protein labeling the thick ascending limb of Henle). In addition, an antibody to proliferating cell nuclear antigen was applied to determine the proliferation index (proliferating cell nuclear antigen-positive nuclei/all counted nuclei x 100, ie, the percentage of proliferating cell nuclear antigen-positive nuclei) of the various atrophic and "super" tubules in ESRD. Classic atrophic tubules and the "super" tubules showed primarily a proximal phenotype. Tubules showing thyroidization were consistently positive with markers of the distal tubular epithelium. "Endocrine" tubules stained primarily with distal tubular markers; however, some proximal staining also was noted. The widened renal interstitium contained single cells or loosely organized small cell clusters positive with both the AE1/AE3 and the epithelial membrane antigen antibodies. Serial sectioning showed that the majority of these single cells were not forming tubules. The proliferation index of the "classic" atrophic tubules was the highest (3.08%), followed by the "super" tubules (2.39%), the "endocrine" tubules (1.58%), and the "thyroid" tubules (1.09%). These indexes are all considerably higher than the proliferation index of the normal renal tubular epithelium. Our findings suggest that different types of tubular atrophy may arise from different segments of the nephron, and that the renal interstitium in ESRD may harbor isolated cells with epithelial characteristics. Furthermore, the end-stage kidney is not a resting organ; on the contrary, it shows a high proliferative activity, particularly in the epithelium of the "classic" atrophic and the "super" tubules.

Passive hemagglutination inhibition test for diagnosis of brown recluse spider bite envenomation.

Our goal was to recreate a passive hemagglutination inhibition (PHAI) test to diagnose brown recluse spider (BRS; Loxosceles reclusa) bite envenomation for treatment trials. Guinea pigs received intradermal injections of concentrated spider venom from the following species: Loxosceles reclusa, Argiope aurantia, Argiope trifasciata, Phidippus audax, and Lycosa frondicola. Skin lesion exudate was collected and tested with the BRS venom PHAI assay. From 51 separate collections of exudate, test sensitivity was 90% as long as 3 days after venom injection. Specificity was 100% with venom from the other spider species listed above in vivo (7 test samples) and in vitro (5 test samples), as well as with random bacterial exudate with and without added serial dilutions of BRS venom (10 test samples). The test was reproducible over repetitive assays to within one 10-fold dilution. A positive PHAI test result could function as an entry criterion for BRS bite victims in human treatment trials.

Sequential renal alterations in septic shock in the primate.

This is a descriptive sequential study of the response of the baboon to LD100 Escherichia coli. The response was found to consist of three stages based on electron microscopic, physiologic, and clinical laboratory data. This study associates the inflammatory, coagulant, and cell injury (stage 1-3) responses with markers of activation of inflammatory cells (tumor necrosis factor) and of the vascular endothelium (tissue plasminogen activator). This work also shows that in contrast to the underlying parenchymal cells of the organ, the vascular endothelium remains intact throughout the response to LD100 E. coli. The possible role of the vascular endothelium in mediation of events at both its luminal (blood) and antiluminal (parenchymal) surfaces is discussed.

Serum creatine kinase-BB and small cell anaplastic carcinoma of the lung: two case reports.

Recent reports have suggested that serum creatine kinase isoenzyme BB (CK-BB) may be used as a tumor marker for a variety of malignancies, particularly prostatic carcinoma. Two cases of small cell anaplastic carcinoma of the lung (SCAC) had markedly contrasting levels of CK-BB by serum electrophoresis. Retrospective analysis of the index cases, and four additional autopsy cases of SCAC, included: 1) quantitation of CK-B in postmortem tumor and adjacent non-tumor lung tissue; 2) enzymatic and radioimmunoassay serum levels of CK-B; and 3) CK-B immunoperoxidase staining of tumor and non-tumor tissues for CK-B. Serum CK-BB is a non-specific tumor marker, but its presence, in whatever amount, should alert the clinician to the possibility of an associated malignancy, particularly SCAC or metastatic carcinoma.

A validation study of selected methods routinely used for measurement of cyclosporine.

We compare four methods for measuring cyclosporine (CyA) in plasma and whole blood of transplant patients: HPLC, RIA with a polyclonal antibody, RIA with a monoclonal antibody, and fluorescence polarization immunoassay (FPIA). The monoclonal RIA procedure correlated acceptably with HPLC, with slope = 1.21, r = 0.97, and Sy,x = +/- 40.1. However, the FPIA, done in three separate instruments, correlated relatively poorly with HPLC, giving slopes of 1.67, 1.51, and 2.32; correlation coefficients of 0.72, 0.43, and 0.83; and Sy,x = +/- 205.4, +/- 334.5, and +/- 222.4. The polyclonal RIA correlated reasonably well with HPLC, with a slope = 1.15, r = 0.90, and Sy,x = +/- 72.6. Values for individual patients with increases both in gamma-glutamyltransferase and creatinine showed very poor correlation between FPIA and HPLC, which suggests that metabolite cross-reactivity with FPIA is significant and unpredictable in patients with liver dysfunction coexisting with renal dysfunction. Evidently, the monoclonal RIA can be substituted for HPLC, if the therapeutic range is adjusted for the 21% higher results obtained by RIA.

Hypercalcitoninemia and hypocalcemia in acutely ill children: studies in serum calcium, blood ionized calcium, and calcium-regulating hormones.

We studied the hypotheses that serum calcium and blood ionized calcium would be low in acutely ill children and would rise with clinical improvement. In 15 children admitted to the pediatric intensive care unit, the blood ionized calcium level was 4.45 +/- 0.06 mg/dl (1.11 +/- 0.015 mmol/L) on entry versus 5.17 +/- 0.03 mg/dl (1.29 +/- 0.01 mmol/L) in control subjects (p less than 0.005), rose significantly on days 2 and 3, and was 5.12 +/- 0.04 mg/dl (1.28 +/- 0.01 mmol/L) at discharge (p less than 0.005). Changes in serum calcium level were similar, whereas serum magnesium and phosphorus levels were normal and did not change. Basal serum parathyroid hormone concentrations were elevated, rose further during the study, and were normal at discharge. Serum parathyroid hormone levels correlated inversely with blood ionized calcium levels, indicating that compensatory hyperparathyroidism occurs with low blood ionized calcium concentrations. Basal serum calcitonin values were evaluated on entry and decreased with clinical improvement. Serum calcitonin levels correlated significantly with low blood ionized calcium levels, indicating that hypercalcitoninemia may play a role in the pathogenesis of hypocalcemia in these children. Urine calcium excretion was not increased in the four children studied. We speculate that with clinical improvement, a rise in serum parathyroid hormone levels and a decline in serum calcitonin levels may help restore normocalcemia in these acutely ill children.

Antithrombin-III prevents the lethal effects of Escherichia coli infusion in baboons.

Infusion of Escherichia coli (LD100) was followed by coagulopathic and cell injury responses, cardiovascular collapse, and death in 18 to 32 hr in four out of four baboons. Infusion of AT-III in sufficient amounts to achieve AT-III levels of more than 4 units/ml of plasma before and during the infusion of E. coli reduced the intensity of the coagulopathic and cell injury response and prevented vascular collapse and death in four out of four baboons. Failure to achieve AT-III levels of more than six units/ml at T +60 min during the infusion of E. coli resulted in failure to prevent its lethal effects in three out of three baboons even though levels as high as 10 units/ml were achieved later in the course of the experiment. These studies suggest that thrombin and/or its products can contribute to the inflammatory response to E. coli and that AT-III is of potential value as a prophylactic but not as a therapeutic agent in the treatment of patients at high risk of developing gram negative sepsis.

Effect of mineral supplementation of human milk on bone mineral content and trace element metabolism.

We studied the effect of feeding mineral fortified human milk to preterm infants (birth weight less than or equal to 1500 gm). Serum concentrations of calcium, magnesium, phosphorus, zinc, cooper, alkaline phosphatase, and parathyroid hormone were determined, and bone mineral content was measured, in infants fed unfortified human milk (group 1), fortified human milk (group 1), fortified human milk (group 2), and a "humanized," mineral-enriched premature infant formula (group 3). Serum calcium, magnesium, phosphorus, zinc, copper, and parathyroid hormone concentrations did not differ significantly among the groups studied. Serum alkaline phosphatase concentrations increased significantly only in the infants fed unfortified human milk, and bone mineral content in this group was significantly lower than in formula-fed infants.

Lowered serum Ca, blood ionized Ca, and unresponsive serum parathyroid hormone with oral glucose ingestion in infants of diabetic mothers.

Oral glucose ingestion may lower serum Ca in infants of diabetic mothers (IDMs). Six metabolically stable IDMs were studied following ingestion of 1.7 +/- 0.1 g/kg (mean +/- SE) of glucose over 20 min and serum Ca, Mg, P, blood iCa, serum PTH, and CT were measured at 0, 1/2, 1, and 2 h. Data obtained in IDMs were compared with previously reported findings in 10 normal neonates. In IDMs as in normal neonates, serum Ca, Mg, P declined significantly after oral glucose ingestion. Blood Ca2+ was significantly lower at +1/2 h in IDMs versus normal neonates, and by analysis of covariance, trends in blood Ca2+ were significantly different in IDMs versus normal neonates, (p less than 0.05). Serum PTH concentrations were unaltered in IDMs versus a significant rise in serum PTH noted in normal neonates. The difference between the two groups was significant statistically (p less than 0.05). Baseline serum CT was elevated in both groups and did not change. Thus, in IDMs responses to oral glucose ingestion differs from that seen in normal neonates as follows: blood Ca2+ is lowered in IDMs versus normal neonates, and serum parathyroid hormone (PTH) does not respond to a decline in blood Ca2+ in IDMs, whereas in normal neonates serum PTH rises and blood Ca2+ is maintained. We speculate that relative parathyroid gland unresponsiveness occurs in IDMs, which may result in lowered blood Ca2+ after oral glucose ingestion in these infants.