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Colloidal gold immunochromatographic assay (CGIA) is commonly used for the on-site detection of β-agonists that are sometimes used illegally as feed additives in swine diets. However, few studies have evaluated the causes of false-positive results that sometimes occur when applying CGIA in agricultural settings. In this study, we investigated if this false-positive phenomenon is related to the addition of certain traditional Chinese medicines (TCMs) to swine feed. We established and verified an extraction method for TCMs, and then applied CGIA to detect β-agonists in the extracts of 105 TCMs and in the urine of swine dosed with TCMs, respectively. Liquid chromatography-tandem mass spectrometry was used to validate the results of the urine samples tested positive for β-agonists using CGIA. The results were also verified using TCMs and colloidal gold test strips produced by different manufacturers. The extracts of Citri Reticulatae Pericarpium Viride, Citri Reticulatae Pericarpium, Magnoliae Officinalis Cortex, Chaenomelis Fructus, and Rhodiolae Crenulatae Radix Et Rhizoma were tested positive for β-agonists. Meanwhile, the addition of Citri Reticulatae Pericarpium Viride and Citri Reticulatae Pericarpium to swine feed resulted in false-positive results for β-agonists in swine urine. The results provide a new way to explain false-positive CGIA results and provide valuable information for livestock feeding programs.

Rapid influenza diagnosis can facilitate targeted treatment and reduce antibiotic misuse. However, diagnosis efficacy remains unclear. This study examined the efficacy of a colloidal gold rapid test for rapid influenza diagnosis. Clinical characteristics of 520 patients with influenza-like illness presenting at a fever outpatient clinic during two influenza seasons (2017–2018; 2018–2019) were evaluated. The clinical manifestations and results of routine blood, colloidal gold, and nucleic acid tests were used to construct a decision tree with three layers, nine nodes, and five terminal nodes. The combined positive predictive value of a positive colloidal gold test result and monocyte level within 10.95–12.55% was 88.2%. The combined negative predictive value of a negative colloidal gold test result and white blood cell count > 9.075 × 109/L was 84.9%. The decision-tree model showed the satisfactory accuracy of an early influenza diagnosis based on colloidal gold and routine blood test results.

African swine fever (ASF), caused by African swine fever virus (ASFV), was first reported in Kenya in 1921, but an effective vaccine or antiviral drug is still not available for ASFV control. Rapid and effective diagnostics are key steps in managing ASF. We generated two monoclonal antibodies (MAbs) against the ASFV phosphoprotein P30 and designated these as 3H7A7 and 6H9A10. Epitope mapping revealed that MAb 3H7A7 and 6H9A10 recognized aa 144-154 and aa 12-18 of P30, respectively. A signal-amplified sandwich colloidal gold test strip for rapid detection of ASFV was developed based using these MAbs. Sensitivity and specificity analysis showed that the detection limit of the strip was 2.16 ng of P30. The strip only reacted with ASFV and did not react with other common porcine viruses. In detection tests using 153 clinical field samples including sera, plasma, anticoagulant-treated blood, and tissue, the strip had 95.42% concordance with real-time PCR. The new MAbs specific for P30 and the rapid colloidal gold test strip helped to reveal novel B cell epitopes in P30 and provide an efficient diagnostic test for on-site clinical detection of ASF.

Nanogold enhanced surface plasmon resonance (SPR), colloidal gold immunochromatographic test strips (ICTS), and polymerase chain reaction (PCR), combined with immunomagnetic separation (IMS) were established in this study for the rapid detection of Vibrio parahaemolyticus (VP). The sensitivities of SPR, ICTS, and PCR was determined to be 101, 103, and 103 CFU/mL for VP, respectively. After separation and enrichment by IMS, the sensitivities of SPR, ICTS, and PCR were 100, 101, and 102 CFU/mL for VP, respectively, which were improved by 10-, 100-, and 10-fold compared to the direct detection by SPR, ICTS, and PCR, respectively. When the VP-polluted water samples were directly assessed by SPR, ICTS, and PCR, the results were negative. By contrast, after separation and enrichment for 45 min by IMS, the results were all positive. The IMS-SPR, IMS-ICTS, and IMS-PCR detection methods were able to yield results in approximately 1.5 h, 55 min, and 3.5 h, respectively. These combined detection methods have advantages in being high-throughput and easy to operate without the need for sophisticated equipment or specialized skills. These methods might aid in the development of SPR, ICTS, and PCR technologies for simultaneously examining multiple food-borne pathogens in food products.

Avian leukosis virus (ALV) is an avian oncogenic retrovirus that induces leukemia-like proliferative diseases in chickens. ALV infection can result in the development of immunological tolerance and persistent viremia. Since effective vaccines against ALV are not yet available, its current prevention primarily depends on detection and eradication to establish exogenous ALV-free poultry flocks. In this study, a rapid and simple colloidal gold test strip method, specific for the group-specific antigen, p27 protein, was developed and systematically evaluated for the detection of ALV from different samples. The detection limit of this assay was as low as 6.25 ng/ml for p27 protein and 80 TCID50/ml for different subgroups of ALV. Besides, the test strip showed high specificity in the detection of different subgroups of ALV, including ALV-A, ALV-B, ALV-J, and ALV-K, with no cross-reaction with other avian pathogens. Furthermore, we artificially infected specific pathogen-free (SPF) chickens with ALV-J, collected cloacal swabs, and examined viral shedding using both test strips and ELISA. Results from the test strip were highly consistent with that from ELISA. In addition, 1104 virus isolates from anti-coagulant blood samples, 645 albumen samples, and 4312 meconium samples were tested, and the test strip results agreed with those of ELISA kit up to 97.1%. All the results indicated that the colloidal gold test strip could serve as a simple, rapid, sensitive, and specific diagnostic method for eradication of ALV in poultry farms.

To quantitatively detect the on-site test of the content of clenbuterol in pork, a photoelectric apparatus for the colloidal gold test to detect clenbuterol was developed based on green LED and linear CCD. This design method could realize a semi-quantitative analysis of clenbuterol concentrations ranging from 0 to 1 ng/ml. Such an apparatus could promote an integrated approach to the management of the community food safety

Fe nanowires/chitosan nano-composites were prepared and their capacity for adsorbing bovine serum albumin (BSA) was examined. The results show that when pH of buffer solution was set at 6.0, the maximum adsorption was 148.40 mg g −1 . By crosslinking α-human chorionic gonadotropin (α-HCG), biological probes with Fe nanowires/chitosan/antibody were prepared. immunochromatographic strips were manufactured, and different concentration HCG antigens were tested. The results indicate that the sensitivity is 10 IU l −1 . Pregnancy can be detected by these immunochromatographic strips 2–3 days earlier than by the colloidal gold test strips in the market.

Numerous studies have demonstrated that fetal fibronectin (fFN) is an excellent marker of preterm delivery with a negative predictive value (NPV) >99% for predicting delivery within 7 or 14 days in symptomatic women (1)(2)(3). Interestingly, these studies have been performed by sending the sample to Adeza Biomedical for testing using an ELISA microtiter plate or by a rapid colloidal gold test marketed only outside the US. In the US, however, the only method available for rapid fFN analysis is the TLi™ system (Adeza Biomedical). Our objective was to assess the utility of the TLi rapid fFN system to predict delivery in symptomatic patients within 7, 14, or 21 days. We used 501 cervicovaginal samples consecutively received in the Barnes-Jewish Hospital Laboratory for physician-ordered fFN analysis during an 18-month period for the study (February 2001–August 2002). From this cohort, charts for 243 patients were available for review. This constitutes the group of patients who delivered at Barnes-Jewish Hospital. Study inclusion criteria included the following: signs …

In a previous communication1 a method was described for the detection and titration of immune bodies in poliomyelitis, with reference to the applicability of the test in the study of susceptible persons, carriers, therapeutic value of serums from normal adults, and in relation to prognosis and convalescence.A total of 363 serums has been studied to date. These included 100 normal adults and 100 normal children (age groups 6 weeks to 19 years), 58 convalescent serums (monkey, adult human, and children), 76 normal animals (monkey, horse, goat, and sheep), and 29 immune animal serums (monkey, horse, goat and sheep).The results have agreed with known facts. The specificity of the test has been demonstrated also by observations made during all stages of poliomyelitis in the human and in the monkey.The progressive development of immune bodies could be shown to occur during convalescence, particularly in those cases where rapid and complete recovery ultimately took place. These antibodies could not be found in t...

(1) The cephalin-cholesterol flocculation test, theintravenous hippuric acid test and theserial brom-sulphthalein test are recommended for routine use as hepatic function tests. These three newer tests are much more sensitive than the two older tests, viz. the Rosenthal bromsulphthalein and theoral hippuric acid tests. These newer tests are reliable. (2) In any comprehensive evaluation of suspected liver damage innon-jaundiced cases, all three of the above mentioned newer tests should be used. Injaundiced cases, the cephalin flocculation test and theintravenous hippuric acid test should be used to evaluate liver function. (The bromsulphthalein test is not reliable in the presence of jaundice). (3) For reasons outlined above, the colloidal gold test is not well adapted to routine clinical use. (4) Although less sensitive than the newer tests, the oral hippuric acid test is ofproven value in cases with known liver disease in determining operative risk. (5) The Rosenthal bromsulphthalein test should be replaced by the serial bromsulphthalein method.

ALTHOUGH the colloidal gold test has been used extensively for half a century,1the basis for the reaction has not been completely clarified. Early investigators found that the globulin fraction of the cerebrospinal fluid (CSF) was responsible for percipitation of the gold sol, while albumin tended to "protect" the gold from precipitation.2-5The various reactions were believed to result from a balance of oppositely charged substances.2Subsequent studies demonstrated that only the gamma globulin fraction was responsible for coagulation and that elevation of this component often resulted in a positive test.6,7 Although this observation has been confirmed by many workers,8-11in some instances quantitative changes alone could not explain the results. Positive reactions may occur with normal amounts of gamma globulin, while considerable increases in this component (without significant elevations of other fractions) have been associated with negative reactions.12-15Such observations suggest that qualitative

1. The cerebro-spinal fluids of 2,000 cases of mental deficiency of both sexes, all grades and ages, were examined. 2. In 1,500 of these cases, observations were made on the after-effects of lumbar puncture. 17% developed post-lumbar puncture symptoms; 142% vomited, 6.8% had headache and 0.73% pyrexia up to 101° F. The incidence of vomiting was nearly twice as high in females as in males, being 20.1% and 10.5% respectively. It was also higher in the feeble-minded group than in the imbecile or idiot group. 3. There was a direct relationship between the rate of flow of the cerebro-spinal fluid and the incidence of post-lumbar puncture symptoms. Where the former was rapid, the incidence tended to be high, and where it was slow, the incidence was relatively low. 4. The tests used on the cerebro-spinal fluid were the Wassermann reaction, cell estimation, Pandy, Lange's colloidal gold, and the acetic anhydride test of Boltz. Many pseudo-positive Pandy and Boltz reactions were given by the fresh cerebro-spinal fluid. 5. Of the 2,000 cerebro-spinal fluids examined, 55, or 2.7% were abnormal. The Wassermann reaction was positive in 19 cases, excess of cells existed in 32, excess of globulin in 44, and the colloidal gold reaction was positive in 30. 6. 23.9% of congenital syphilitics had abnormal cerebro-spinal fluids. 7. The incidence of abnormal cerebro-spinal fluids was higher in those cases of mental deficiency complicated by epilepsy or paralysis than in those free from such complications. 8. The cerebro-spinal fluid of only 1 out of 54 mongolian defectives gave a positive Lange's colloidal gold test. In the remaining 53, the cerebro-spinal fluid was normal in every respect.

ERRONEOUS diagnoses of neurosyphilis are sometimes made in cases of neurologic syndromes because of a history and serologic evidence of syphilis and the presence of abnormalities in the cerebrospinal fluid. It is generally recognized that examination of the cerebrospinal fluid is essential for the diagnosis of neurosyphilis. As shown in a previous report, 1 the reagents and procedures used in such tests should be quantitatively standardized in order to yield accurate and reproducible results. They should include a cell count, determination of total protein and a colloidal gold test of the cerebrospinal fluid, as well as quantitative complement fixation tests of both the cerebrospinal fluid and the blood. 2 Furthermore, the results of the tests of the cerebrospinal fluid should have a quantitative relation to each other, so that together they form a syndrome reflecting the activity and character of the syphilitic inflammatory process. The result of each test should

I. In the cases diagnosed clinically as cerebrospinal syphilis the Wassermann reaction upon the spinal fluid was always positive and the colloidal gold test showed a reaction in the paretic zone. II. In paresis the colloidal gold test was always found positive in cases where the spinal fluid showed a similar reaction to the Wassermann test, in addition to which there is one instance noted in which the fluid Wassermann was negative, but a reaction in the luetic zone obtained by the gold solution. III. In dementia praecox, manic-depressive insanity, arteriosclerotic dementia and epilepsy there were no positive Wassermann reactions upon the fluid, and likewise no response to the gold solution in the typical "paretic zone". However, the latter reagent did furnish in eight cases of the 152 examined a reaction within the minor limits of the "luetic zone." IV. In the unclassffied psychoses the calloidal gold and the Wassermann reactions upon the fluid ran a parallel course, except in one case, which showed a nega...

Serum proteins were examined by flocculation tests and by paper electrophoresis in 246 patients. The colloidal gold test was found to be a fairly good, but not invariabty reliable, criterion of Hashimoto's disease when other causes of abnormality have been excluded. The albumin/γ-globulin ratio was also found to be a useful diagnostic criterion in Hashimoto’s disease. The contention could not be maintained that the primary factor in this disorder is failure of the thyroid cells. In hypothyroidism apart from Hashimoto’s disease, the β-globulin fraction was increased and the γ-globulin fraction was normal. The reverse was true in Hashimoto’s disease.

The value of quantitative cerebrospinal fluid γ-globulin determinations as an aid in neurological diagnosis has been well established in recent years. Although an abnormal colloidal gold test indicates a relative increase in cerebrospinal fluid γ-globulin in many cases, colloidal gold curves are abnormal in only about one third of fluids showing a pathological increase in γ-globulin content when the latter is quantitatively determined. 1 The immunochemical method of measuring cerebrospinal fluid γ-globulin, described by Kabat, Glusman, and Knaub, 2 gives highly reproducible results but has the disadvantage of being somewhat time consuming, and this factor limits its usefulness for routine clinical purposes. The same disadvantage applies to electrophoretic techniques, which, in addition, require the concentration of relatively large volumes of spinal fluid. Another method for estimating cerebrospinal fluid γ-globulin employing zinc sulfate precipitation has been advocated; the zinc sulfate method, however, does not specifically measure γ-globulin, a fact clearly

It has been the general experience in the clinical laboratory that the preparation of a proper colloidal gold solution, that is, a solution which will prove ideal for carrying out the colloidal gold test as applied to the differentiation of cerebrospinal syphilis, is often fraught with certain difficulties frequently not under the control of the worker. With due regard for the proper cleansing of glassware, the purity of the reagents entering into the preparation of such a solution and temperature precautions as laid down by those 1 who have investigated the nature of colloid chemistry as highly necessary prerequisites for the achievement of a good product, it is not infrequently found that such solutions thus prepared are far from being suitable, if not altogether unsuitable, for the test proper. Excluding those colloidal gold solutions that are grossly bad or self-condemnatory by their physical appearances, that is, either turbid or of

The De Paul Sanitarium in New Orleans, an institution for the treatment of nervous and mental disorders, is advantageously situated in regard to climate and for securing malarial organisms. Rarely is it necessary to wait any prolonged period of time before obtaining the tertian type of organisms used in this work. It is also noteworthy that we get cases that are not of the usual state institutional type; that is, dilapidated patients, but also cerebrospinal syphilitic patients who are just beginning to manifest psychic symptoms of dementia paralytica and in whom serologic examination reveals early changes in the paretic zone in the colloidal gold test. On account of this wide variance in the grade of patients with dementia paralytica it has given me an opportunity to conclude distinctly that malarial therapy is undoubtedly best in these early cases and that little improvement may be expected from those in the late

The investigations reported in this paper have to do with various chemical, physical and immunologic studies of the cerebrospinal fluid and blood of syphilitics and nonsyphilitics and, also, with the factors concerned in the colloidal gold and the Wassermann reactions. The experiments fall more or less into two groups and so, for convenience in discussion, we have divided our paper into two parts: I. Ultrafiltration of Syphilitic Serum; II. The Substances Concerned in the Colloidal Gold Test and the Nature of the Reaction. Ultrafiltration of Syphilitic Serum Part I I. INTRODUCTION The nature of the active substance concerned in the Wassermann reaction has been discussed by many authors and numerous theories have been advanced as to the nature of this substance. Citron and Reicher 1 regarded it to be of a lipoid nature. Berczeller and Schillinger 2 extracted syphilitic serum by ether and alcohol. The Wassermann reaction on the serum was weakened

There is an urgent need of a simple, inexpensive and reliable serologic test to differentiate general paresis, and especially incipient general paresis, from other forms of neurosyphilis. The colloidal benzoin reaction of the spinal fluid, first advocated by Guillain, Laroche, and Lechelle 1 as a specific test for neurosyphilis seems more nearly to fulfil these requirements than either the Lange 2 colloidal gold test or the gum mastic test of Emanuel. 3 Warwick and Nixon, 4 using the colloidal gold test, found that out of a total number of twenty spinal fluids from paretic patients, there were two so-called second or tabetic zone curves, and out of seventy-three spinal fluids from tabetic patients there were seven so-called first or paretic zone curves. The error was about 10 per cent, in each. Warwick 5 later, in discussing the effect of treatment on the colloidal gold reaction, gave the curves obtained with

Silver Arsphenamine Argyria (Two Cases). Presented by Dr. Spiegel. F. B., aged 54, said that he had been treated for gonorrhea nineteen years previously. He had received three intravenous injections for syphilis twelve years before presentation. The patient first came under observation on Dec. 10, 1925, for treatment for tabes. The symptoms consisted of pains in the legs, anisocoria, Argyll Robertson pupils, positive Romberg sign, absence of deep reflexes and paresthesia of both legs. The Wassermann tests of the blood and spinal fluid gave negative results. There were 8 cells, and the globulin test gave negative results. The colloidal gold test gave a reaction of 00023320000. From Dec. 10, 1925, to Nov. 5, 1926, he received a course of treatment with injections of arsphenamine, mercury and bismuth. From May 25, to Dec. 29, 1927, he received a course of treatment with silver arsphenamine and bismuth. From March 7, to Dec. 28, 1928, he received two courses of treatment consisting

It is now generally accepted that the physician who undertakes to treat syphilis is failing in his duty to the patient if he neglects routine studies of the spinal fluid. Studies carried out in this clinic 1 and elsewhere have shown that in addition to the procedures of cell count, globulin estimation and Wassermann reaction, there should be included the performance of a colloidal test such as the colloidal gold test of Lange which yields much information of diagnostic and possibly of prognostic import. Unfortunately, the preparation of the colloidal gold solution is so complex, 2 demanding absolute chemical cleanliness of all glassware and the use of triply distilled water, and the solution when prepared is so unstable that the use of this test is practically confined to large laboratories in centers of population. Recent studies have shown that results analogous to those of the gold test may be obtained with colloidal

While there is considerable disagreement between investigators as to the exact value of the various observations with Lange's colloidal gold test for cerebrospinal fluid,1all are unanimous in their opinion regarding its value as a useful confirmatory test in the diagnosis and the differentiation of syphilitic and nonsyphilitic diseases of the central nervous system. The test is based on the observations of Zsigmondy2that proteins will protect various colloidal substances from being precipitated by electrolytes. The degree of protection has been found to be specific for each protein, and is expressed in terms of milligrams of the protein that is capable of protecting 5 cc. of colloidal gold against 0.5 cc. of a 10 per cent solution of sodium chloride. It has been known for a long time that the protein content in spinal fluid varies in pathologic conditions of the central nervous system. Accordingly, Lange took advantage of Zsigmondy's observations and endeavored to apply them to the quantitative determination of protein in the spinal fluid; however, contrary to his expectation, he found that an excess of protein precipitated colloidal gold instead of protecting it.

In a paper published in 1918, we1reported an intensive study of this subject in the neurologic wards and serologic laboratory of the Mount Sinai Hospital. We now desire to bring our experiences down to date and to express our present views. In the light of a tendency to overemphasize the importance of early spinal fluid reactions, we have deemed it expedient critically to review these reactions and to estimate their significance as regards changes in the nervous system, and their proper relation to the nature and intensity of treatment. Our knowledge of cytodiagnosis of the cerebrospinal fluid began with the work of Widal, Ravaut and Sicard2in 1900. The addition of the Wassermann test, protein estimation and the colloidal gold test placed the diagnosis of syphilis of the central nervous system on a definite basis. PRECLINICAL CHANGES IN SYPHILIS CF CENTRAL NERVOUS SYSTEM Ravaut showed that during

I. The Preparation of the Reagent J. H. BLACK, M.D., AND LOUIS ROSENBERG, M.D. To one who has even a casual acquaintance with the literature of colloidal gold solutions, three things are at once apparent: 1. There is a general agreement that satisfactory solutions are difficult of preparation. 2. There are approximately as many variations in technic as there are workers. 3. There is unanimity of opinion that the use of the solution in the diagnosis of diseases of the central nervous system has a very definite value. The major portion of the work done in this country has been carried on with a more or less close adherence to the technic of Lange, 1 variations being introduced by the individual worker in the effort to produce uniform results. It is quite true that many men have been able to produce satisfactory solutions -some of them with considerable regularity —

Examinations were made of the spinal fluid and blood of all new patients admitted to the men's division at Central State Hospital, Indianapolis, during 1932 and 1933. Examination of the spinal fluid included: Ross and Pandy tests; cell counts; the colloidal gold test, and the Wassermann, Kahn and Kline tests. In 1932, 28 (22.3 per cent) of 125 psychotic patients admitted had typical clinical dementia praecox. Of these, 32 per cent gave positive serologic reactions as tabulated. In 1933, 35 (22.3 per cent) of 156 psychotic patients admitted had dementia praecox. Of these, 28.5 per cent gave positive serologic reactions, as shown in the following tabulation. Of the 1932 group of patients with dementia praecox, 19 (68 per cent) gave completely normal serologic reactions. Six of these 19 patients were discharged as improved or recovered, but the remaining 13 did not improve sufficiently to be furloughed. Similarly, in the 1933

Although the colloidal mastic test, first introduced by Emmanuel,1and later modified by Cutting,2has been in limited use for several years, the question of its value as compared with that of the colloidal gold test is still an unsettled one. Considering the more complicated and uncertain methods of preparing the reagents used in the colloidal gold test, the simplicity and uniformity of the mastic reaction has much to recommend it. If it can be shown that the information provided by the mastic test is equivalent to that given by the gold test, or that the mastic test may in some cases provide information which the gold test fails to give, the test deserves wider use than is now made of it. In either case, the mastic test should prove of value not only when facilities for performing the gold test are lacking, but also as a check

Marked advances in the diagnosis of organic nervous diseases have been made in the past few years. This is in a great measure due to the careful and frequent studies of the spinal fluid in our obscure neurologic cases. The importance of Nonne's four tests, to which may be added a fifth, Lange's colloidal gold test, are demonstrated in the following case. The combination of cerebrospinal syphilis with pneumococcic meningitis seemed of sufficient interest for publication. A woman, aged 21, single, domestic, with negative family and personal history, except for an appendectomy in 1911, stated that about two years ago she had a sore on her hand, which the doctor pronounced a gonorrheal infection. Syphilis was denied. The present complaint began about Jan. 10, 1915, when the patient developed an abscess on her right thumb which was very painful. This continued to suppurate slightly for one week, and January 17

The object of this study is to present for comparison the results of 400 reactions of cerebrospinal fluids with the colloidal gold, benzoin and mastic tests. A brief survey of the literature on colloidal tests is summarized in Table 1. Lange, 1 in 1912, added the colloidal gold test to the examination of the cerebrospinal fluid. In 1915, Emanuel's 2 colloidal mastic test furthered such colloidal studies. Cutting, 3 in 1917, modified the mastic test. This modification was the addition of potassium carbonate to the saline solution. Results, both favorable and unfavorable, have been contributed by many observers on the value of the colloidal mastic test. In 1920, Guillain, Laroche, and Lechelle 4 produced the original technic of the colloidal benzoin test. Sixteen test tubes were used, and the dilutions were made with a weak solution of sodium chlorid. This technic was repeatedly simplified until a test of five tubes

The literature contains few reports on the spinal fluid in postdiphtheritic paralysis, and these refer to records usually of only one or two cases, with investigation restricted to the routine examination for albumin, sugar and cells. Among the authors who have contributed data on the subject are De Massary, Dufour, Comby and Netter, 1 Marfan, 2 Rohmfeld, Chauffard and Le Conte, 3 Ravout and Krolinetsky, 4 Hallez and Lortat-Jacob 5 and Regan. 6 De Lavergne 7 has recently given quantitative sugar determinations in three cases, and Regan and Wilson 8 have reported the reactions encountered with Lange's colloidal gold test. It is not too much to say that the extent of the involvement of the nervous system manifest in the many cases of the more severe forms of postdiphtheritic paralysis is an indication for the more careful study of the spinal fluid, not only from the point of view of

The occasional occurrence of a paretic gold curve in cases that were not paresis, and the occasional diagnosis of paresis without a paretic gold curve suggested that a closer study of this particular colloidal gold reaction should be made. A review of the rather extensive literature that has grown up since Lange1first introduced this test in 1912 shows that various conclusions have been drawn concerning the value of the paretic curve. These conclusions, however, were based on a more or less limited number of cases. At this hospital about 8,400 colloidal gold tests have been made on about 7,100 different cerebrospinal fluids. Of this number, 677 fluids gave paretic curves, and these constitute the basis for this study. A large majority of the patients coming to this hospital are in the early stages of their disease, and consequently these findings are those of the early stages, and are

The instability of the colloidal gold solution and the rather uncertain methods used in its preparation have led to numerous attempts to secure a substitute for the gold test. The colloidal mastic test, first introduced by Emmanuel,1and modified by Cutting,2Stanton,3Keidel and Moore,4Smith5and others, has been extensively used, not as a substitute for the gold test, but as an additional test. Keidel and Moore4and Wassermann6found close agreement between the gold and mastic tests; they also found that when agreement was lacking, the mastic test seemed to detect abnormalities in spinal fluids more often than did the gold test. After performing 250 tests with the colloidal mastic in parallel with the colloidal gold test and confirming the results of Keidel and Moore, the former test was adopted as a part of the routine procedure for all specimens of

In 1916 Johnston 1 reported on the use of the colloidal gold test on the spinal fluid in four cases of poliomyelitis. He found an early transitory reaction in the syphilitic zone during the acute stage, and he considered that the test might prove an important aid in diagnosis. In March, 1917, Felton and Maxcy 2 published an excellent and important contribution on the subject. These investigators examined the spinal fluids of fifty-seven patients during various stages of the disease, and came to the following conclusions: (1) In the acute stage of poliomyelitis, the spinal fluid reacts with colloidal gold in dilutions of 1:40 to 1:60 producing a maximum decoloration of 3. (2) In the second and third weeks the reaction is practically the same, with a tendency to clear up in some cases and a precipitation in higher dilutions in others. (3) From the fourth to the eighth week

To the Editor:— Nicholas J. Fiumara, MD (Question and Answers, 208 :2168, 1969), stated in reply to a question about Lange's colloidal gold test, that it "offers little more in diagnostic help than the total protein test [of cerebrospinal fluid]." This statement may be valid in respect to the diagnosis of neurosyphilis but is incorrect if applied to neurologic diagnosis in general. 1 Multiple sclerosis and subacute sclerosing panencephalitis are two diseases often associated with an abnormal gold curve in the presence of a normal cerebrospinal fluid total protein value. In fact, an abnormal gold curve may call attention to these diagnostic possibilities, when they have not been previously suspected. In such cases a sample of cerebrospinal fluid should be sent to a more specialized laboratory which can perform electrophoretic studies.