SINGLE MOST IMPORTANT TESTS

Collected from prepcenter at www.prep4usmle.com
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for wilson disease,

liver biopsy ( not ser cerulosplasmin)



for pry scl cholangitis

is ERCP or Transhepatic cholangiogram ( not liver biopsy)




for hep B and C

is liver biopsy.



the best screening test for SLE is ANA. if negative then SLE can be ruled out.


joint fluid analysis is used in making diagnosis of acute gout. uric acid levels are not useful. some people may have high level and no gout. uric acid level may be normal or low level during a gout episode



ser cr kinase and aldolase (raised up to 50x) in suspected cases of inflammatory myopathy

confirm with muscle biopsy


CT Scan for head injury.

no need for contrast cos blood does not enhance


in the first hrs following subarachnoid bleeding when ct is normal, the single most important test is lumbar puncture ( if RBC is absent then r/o SAH)

for iron def anemia is bone marrow aspirate for fe staining..... this is rarely done.

beware of ser ferritin levels. a low level is specific for fe def but a high level may be seen in malig or inflammation


initial test for MG = anti Ach receptor antibodies ( yes, its not tensilon..the serology is supposed to be better)

best/ most accurate test= EMG

the best test for determining renal artery stenosis is renal angiography

the best NON-INVASIVE test is captopril renogram.


for sarcoidosis is biopsy

ACE levels are elevated ( non-sp...may be used for ff up)
uveitis and conjustivitis seen in 25%


for PULM EMB,

gold standard test for diagnosis is pulm angiog ( this is invasive so it is not the first test to be performed)

V/Q ratio is second best but the one we are more likely to perform first. if it dx PE, no need for angio. in the post op pt, do spiral CT cos v/q are usu abN in these pts.


nil for parkinson's dis

dx is clinical

MRI for MS.


for pemphigus and pemphigoid is skin biopsy and immunofluorescence

pemphigus.....intercellular deposits of IgG and C 3 in epidermis
pemphigoid.....ab at dermo-epidermal junction

for primary syphilis is dark field microscopy.

VDRL and RPR have 25% false negative.

for secondary sypilis, VDRL and RPR have 100% accuracy


for achalasia

best screening is barium swallow

best diagnostic is manometry


in osteomyelitis, when the X ray film is normal, the best test is MRI.

it is same sensitivity with technitium scan but better specificity than it.

single most important evaluation tool for growth evaluation = growth chart.

single most important diagnostic study is xray of left wrist and hand for bone age


most important in ingestion of corrosives=upper endoscopy for determining extent of injury

( not x ray, barium studies etc )


for organophosphorus poisoning, best test is RBC cholinesterase level. takes a while for results to be available so dont wait for results. treat pt based on S+ S.

ser Fe >500ug/dl is severe poisoning
>10% carboxyhb is sympotmatic
>70% leads to death
ser salicylate (6hrs after ingestion)<35mg% ...pt will be asymptomatic
.................................................>100mg% potentially fatal
ser alcohol >100mg% is legally drunk in most states
................>500mg% is fatal in the non-tolerant person
acetaminophen 150mg/kg is toxic for children <12yrs
..........................7.5g in single dose is toxic for adults
ser lead >10ug/dl is abnormal
.............44-7oug/dl....treat with isingle drug eg dmsa
.............>70ug/dl.......hospitalise and treat with 2 drugs



HIV PCR is preferred virology assay for infants with HIV in the developing countries.

(hey this is very expensive....about US$300! most of the pts cannot pay. they would rather wait and see!!!)


gold standard test for obstructive sleep apnoea = polysomnography

for reinfarction within 1-2 weeks

CKMB


best initial test for ovulation

BBT and midluteal progesterone level


similar INITIAL tests for luteal phase defect

confirmatory test= endometrial biopsy


ser Fe >500ug/dl is severe poisoning
>10% carboxyhb is sympotmatic
>70% leads to death
ser salicylate (6hrs after ingestion)<35mg% ...pt will be asymptomatic
.................................................>100mg% potentially fatal
ser alcohol >100mg% is legally drunk in most states
................>500mg% is fatal in the non-tolerant person
acetaminophen 150mg/kg is toxic for children <12yrs
..........................7.5mg in single dose is toxic for adults
ser lead >10ug/dl is abnormal
.............44-7oug/dl....treat with isingle drug eg dmsa
.............>70ug/dl.......hospitalise and treat with 2 drugs


ABDOMINAL ULTRASOUND....study of choice in diagnosis and follow up of abdominal aortic aneurysms..

DISECTING AORTIC ENEURYSM..

diagnosis..

-chest xray ,helical CT scan in stable pts.transesophageal echcardiogram in unstable pts

-gold standard in diagnosis..is aortogram.


polymyositis... best diagnosis is muscel biopsy


Best Initial test for
Ankylosing spondylitis is X-ray of the Sacro-iliac joint

If clinical suspecion is high but X-ray is negative then do a CT scan

HLA-B27 is NOT specific for diagnosis, it's just that if it is negative the diagnosis can be excluded smiling face


Steatorrhoea - fat malabsorption

Quantitative estimation of stool fat

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Carbohydrate malabsorption

D-Xylose test

Herpes Encephelitis

HSV PCR - gold standard

CSF finding is lymphocytic pleocytosis, Increased erythrocytes, elevated protein
mainly affects the temporal lobe