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Tropical Doctor, October 1992
Aldehyde test (Formol-Gel test) in the diagnosis of Kala-azar (visceral leishmaniasis) M A Jalil Chowdhury MBBS FCPS A K M Rafiqueuddin MBBS FCPS Akhtar Hussain FRCP Department of Medicine, Rajshahi Medical College, Rajshahi 6000, Bangladesh TROPICAL DOCTOR,
1992, 22, 185-186
INTRODUCTION
The demonstration of Leishman-Donovan bodies (amastigotes) in spleen, bone-marrow or lymph node aspirates provides the definitive diagnosis of Kala-azar. These procedures have some limitations I,2 because they are not always practicable in rural settings. Specific serological tests are complex, require trained manpower and a well equipped laboratory. People of low socio-economic group residing in the rural area are often the victims of Kala-azar. They are usually beyond the reach of well equipped laboratory facilities. In such circumstances the aldehyde test (AT) (Formol-Gel test), which is nonspecific, is simple to do and less costly. This communication assesses the role of this test in the diagnosis of Kala-azar in a part of the world where the diagnostic facilities are scarce. MATERIALS AND METHODS
Three hundred and seventy-five Kala-azar patients admitted during an 18-month period from October 1988 to March 1990 in all the Medical and Paediatric units of Rajshahi Medical College Hospital, Bangladesh were studied. Two hundred and sixty-five cases were diagnosed on the basis of demonstration of amastigotes of leishmania in the bone-marrow or splenic aspirate. The remaining 110 cases were diagnosed on the basis of strong clinical suspicion, positive complement fixation test (CFT) and positive response to sodium stibogluconate therapy as per WHO recommendation'. AT was done in all the cases. One hundred non Kala-azar patients of different age and sex having fever and/or splenomegaly served as controls. The aldehyde test was done by adding one drop of
commercial formalin (40070 formaldehyde) to 1 ml of serum. Solidification with complete opacity of the serum within 20 min was taken as strongly positive, within 2 h as moderately positive and within 24 h as weakly positive reaction. The antigen used for CFT was obtained from Mycobacterium phlei". RESULTS AND DISCUSSION
Bone marrow aspirations were done on 363 Kalaazar patients out of which amastigotes were demonstrated in 249 (68.6%) cases. In 231 cases, the parasites were found at the first aspirate but two or three attempts were required in the remaining cases. Splenic aspiration was done on 23 bonemarrow negative cases, out of which 16 (70%) yielded positive results. Our impression, therefore, is that if the first attempt fails to detect the parasite, a second bone-marrow aspiration or a splenic aspiration should be tried before excluding Kalaazar. However, both the procedures are painful for the patients and require hospitalization. AT was positive in 94% and CFT was positive in 96% of Kala-azar patients (Table 1). A comparison of the results of AT and CFT reveals that amongst the 278 CFT positive cases, 275 (99%) were also AT positive. There was a significant association between the two tests (P
Tropical Doctor, October 1992
Aldehyde test (Formol-Gel test) in the diagnosis of Kala-azar (visceral leishmaniasis) M A Jalil Chowdhury MBBS FCPS A K M Rafiqueuddin MBBS FCPS Akhtar Hussain FRCP Department of Medicine, Rajshahi Medical College, Rajshahi 6000, Bangladesh TROPICAL DOCTOR,
1992, 22, 185-186
INTRODUCTION
The demonstration of Leishman-Donovan bodies (amastigotes) in spleen, bone-marrow or lymph node aspirates provides the definitive diagnosis of Kala-azar. These procedures have some limitations I,2 because they are not always practicable in rural settings. Specific serological tests are complex, require trained manpower and a well equipped laboratory. People of low socio-economic group residing in the rural area are often the victims of Kala-azar. They are usually beyond the reach of well equipped laboratory facilities. In such circumstances the aldehyde test (AT) (Formol-Gel test), which is nonspecific, is simple to do and less costly. This communication assesses the role of this test in the diagnosis of Kala-azar in a part of the world where the diagnostic facilities are scarce. MATERIALS AND METHODS
Three hundred and seventy-five Kala-azar patients admitted during an 18-month period from October 1988 to March 1990 in all the Medical and Paediatric units of Rajshahi Medical College Hospital, Bangladesh were studied. Two hundred and sixty-five cases were diagnosed on the basis of demonstration of amastigotes of leishmania in the bone-marrow or splenic aspirate. The remaining 110 cases were diagnosed on the basis of strong clinical suspicion, positive complement fixation test (CFT) and positive response to sodium stibogluconate therapy as per WHO recommendation'. AT was done in all the cases. One hundred non Kala-azar patients of different age and sex having fever and/or splenomegaly served as controls. The aldehyde test was done by adding one drop of
commercial formalin (40070 formaldehyde) to 1 ml of serum. Solidification with complete opacity of the serum within 20 min was taken as strongly positive, within 2 h as moderately positive and within 24 h as weakly positive reaction. The antigen used for CFT was obtained from Mycobacterium phlei". RESULTS AND DISCUSSION
Bone marrow aspirations were done on 363 Kalaazar patients out of which amastigotes were demonstrated in 249 (68.6%) cases. In 231 cases, the parasites were found at the first aspirate but two or three attempts were required in the remaining cases. Splenic aspiration was done on 23 bonemarrow negative cases, out of which 16 (70%) yielded positive results. Our impression, therefore, is that if the first attempt fails to detect the parasite, a second bone-marrow aspiration or a splenic aspiration should be tried before excluding Kalaazar. However, both the procedures are painful for the patients and require hospitalization. AT was positive in 94% and CFT was positive in 96% of Kala-azar patients (Table 1). A comparison of the results of AT and CFT reveals that amongst the 278 CFT positive cases, 275 (99%) were also AT positive. There was a significant association between the two tests (P
