Labs & Diagnostics

How respiratory therapists read the complete blood count — the white count and differential, hemoglobin and hematocrit and their link to oxygen-carrying capacity, and the platelet count before invasive procedures.

The basic metabolic panel through a respiratory lens — sodium, potassium, chloride and bicarbonate, the anion gap, and how potassium, phosphate, and magnesium affect respiratory muscle strength and weaning.

What a lactate tells the respiratory therapist — anaerobic metabolism and the oxygen-delivery/demand balance, type A versus type B lactic acidosis, the sepsis thresholds, and lactate clearance as a resuscitation target.

The biomarkers that help separate a cardiac from a pulmonary cause of dyspnea — BNP and NT-proBNP for heart failure, troponin for myocardial injury and right-heart strain, and D-dimer for venous thromboembolism.

Reading the respiratory micro lab — judging specimen quality on the Gram stain, recognizing the common pathogens by clinical setting, and understanding the culture, sensitivity, and acid-fast workup that guide antibiotic therapy.

A respiratory therapist's systematic approach to the chest radiograph — confirming tube and line placement after intubation, and recognizing the common patterns of consolidation, atelectasis, pneumothorax, effusion, and pulmonary edema.

The coagulation labs to check before an invasive respiratory procedure — PT/INR, aPTT, and the platelet count — what they measure, the anticoagulants that affect them, and the bedside thresholds for arterial puncture, bronchoscopy, and chest tubes.

Why a pulse oximeter cannot see carbon monoxide or methemoglobin, and how laboratory co-oximetry measures the true hemoglobin species — carboxyhemoglobin, methemoglobin, and sulfhemoglobin — to expose a saturation gap and guide treatment.

The point-of-care testing respiratory therapists own — bedside blood gas and co-oximetry analyzers — and the quality assurance that keeps results trustworthy: calibration, quality control, proficiency testing, and avoiding pre-analytic errors.

Making sense of a thoracentesis result — Light's criteria for separating a transudate from an exudate, and the pleural fluid pH, glucose, LDH, and cell counts that identify a complicated effusion needing drainage.

A systematic rate-rhythm-axis approach to the ECG for respiratory therapists, then the board-tested rhythm set — from sinus tach and atrial fibrillation to VT, VF, PEA, the AV blocks, and paced rhythms.

High-anion-gap and normal-anion-gap metabolic acidosis side by side — the mechanism, the anion gap, the MUDPILES and HARDASS causes, the urine anion gap, and the labs that work up each.

The hemoglobin species a co-oximeter measures — oxyhemoglobin, carboxyhemoglobin, methemoglobin, and sulfhemoglobin — compared by what they do to the pulse oximeter and co-oximetry, the clinical clues, and the treatment.

The complete-blood-count abnormalities respiratory therapists encounter — leukocytosis and the left shift, eosinophilia, anemia and polycythemia, and thrombocytopenia — with the likely cause and the bedside implication of each.

Separating a cardiac from a pulmonary cause of acute dyspnea by the diagnostics — BNP, troponin, D-dimer, the chest film, the ABG, and the echocardiogram — so the lab picture points to the right organ.